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copyright ? cirrus logic, inc. 2001 (all rights reserved) tx_en tx_er/txd4 txd[3:0] tx_clk mdc mii_irq mdio crs col rx_er/rxd4 rx_dv rxd[3:0] rx_clk rx_en tx+/- rx+/- 10/100 mux 4b/5b decoder descrambler manchester encoder scrambler mlt-3 encoder 10baset filter slew rate control mux 10/100 4b/5b encoder adaptive eq. & baseline wander compensation 10baset filter led drivers 100baset slicer 10baset slicer mlt-3 decoder manchester decoder auto negotiation timing recovery mii control/status registers link management CS8952T 10baset/100base-x transceiver media independent interface (mii) led1 led2 led3 led4 led5 CS8952T advanced product databook c r y s t a l l a n ? 1 0 0 b a s e - x and 10base-t transceiver features n single-chip ieee 802.3 physical interface ic for 100base-tx and 10base-t n adaptive equalizer provides extended length opera- tion with superior noise immunity and next margin n extremely low transmit jitter (<400 ps) n low common mode noise on tx driver for reduced emi problems n integrated rx and tx filters for 10base-t n compensation for back-to-back killer packets n digital interfaces supported media independent interface (mii) for 100base-x and 10base-t repeater 5-bit code-group interface (100base-x) 10base-t serial interface n register set compatible with dp83840a n ieee 802.3 auto-negotiation with next page support n six led drivers (lnk, col, fdx, tx, rx, and spd) n low power (135 ma typical) cmos design operates on a single 5 v supply description the CS8952T uses cmos technology to deliver a high-per- formance, low-cost 100base-x/10base-t physical layer (phy) line interface. it makes use of an adaptive equalizer op- timized for noise and near end crosstalk (next) immunity to extend receiver operation to cable lengths exceeding 160 m. in addition, the transmit circuitry has been designed to pro- vide extremely low transmit jitter (<400 ps) for improved link partner performance. transmit driver common mode noise has been minimized to reduce emi for simplified fcc certification. the CS8952T incorporates a standard media independent in- terface (mii) for easy connection to a variety of 10 and 100 mb/s media access controllers (macs). ordering information CS8952T-cq 0 to 70 c 100-pin tqfp CS8952T-iq -40 to 85 c 100-pin tqfp cdb8952 evaluation board ds206pp3 feb 01 cirrus logic advanced product databook
2 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook table of contents introduction ................................................................................................................ .......... 4 high performance analog ...................................................................................................... .4 low power consumption ........................................................................................................ 4 application flexibility ...................................................................................................... ......... 4 typical connection diagram ................................................................................................... 4 pin descriptions .............................................................................................................. ........ 6 functional description ..................................................................................................... 17 digital system interface ...................................................................................................... ... 17 major operating modes ......................................................................................................... .17 100base-tx nibble mode ........................................................................................... 17 100base-x symbol modes .........................................................................................20 10base-t mii application ............................................................................................ 21 - 10base-t serial application ..................................................................................... 22 - auto-negotiation ............................................................................................................ ...... 22 - auto-negotiation configuration ..................................................................................23 - auto-negotiation operation ........................................................................................ 23 reset operation ............................................................................................................... ...... 24 led indicators ................................................................................................................ ........ 24 media independent interface .......................................................................................... 25 - mii frame structure ......................................................................................................... .... 25 - mii receive data ............................................................................................................ ..... 26 mii transmit data ............................................................................................................. ...... 26 mii management interface ..................................................................................................... 2 7 mii management frame structure .........................................................................................27 configuration ................................................................................................................. ...... 29 configuration at power-up/reset time ..................................................................................29 configuration via control pins ...............................................................................................2 9 configuration via the mii ..................................................................................................... ... 29 CS8952T registers ............................................................................................................. .... 30 basic mode control register - address 00h .......................................................................... 31 basic mode status register - address 01h ........................................................................... 33 phy identifier register, part 1 - address 02h ........................................................................ 35 phy identifier register, part 2 - address 03h ........................................................................ 36 auto-negotiation advertisement register - address 04h ....................................................... 37 auto-negotiation link partner ability register - address 05h ................................................ 38 auto-negotiation expansion register - address 06h ............................................................. 39 auto-negotiation next-page transmit register - address 07h .............................................. 40 interrupt mask register - address 10h ..................................................................................41 interrupt status register - address 11h ................................................................................. 44 disconnect count register - address 12h ............................................................................. 47 false carrier count register - address 13h .......................................................................... 48 scrambler key initialization register - address 14h .............................................................. 49 receive error count register - address 15h ......................................................................... 50 descrambler key initialization register - address 16h .......................................................... 51 pcs sub-layer configuration register - address 17h .......................................................... 52 loopback, bypass, and receiver error mask register - address 18h .................................. 55 self status register - address 19h ........................................................................................ 58 10base-t status register - address 1bh ............................................................................. 60 10base-t configuration register - address 1ch ................................................................. 61 design considerations ......................................................................................................63 twisted pair interface ........................................................................................................ ....63 internal voltage reference .................................................................................................... 63
ds206pp3 3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook clocking schemes .............................................................................................................. ...63 recommended magnetics .....................................................................................................64 power supply and decoupling ...............................................................................................64 general layout recommendations ........................................................................................64 specifications and characteristics ...........................................................................67 absolute maximum ratings..........................................................................................67 recommended operating conditions .....................................................................67 quartz crystal requirements..................................................................................67 dc characteristics ........................................................................................................68 dc characteristics (cont.) .........................................................................................69 switching characteristics.........................................................................................70 mechanical specifications ..............................................................................................82 package dimensions ............................................................................................................ .82 recommended pcb footprint ...............................................................................................83 revision history .............................................................................................................. .....84
4 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook introduction the CS8952T is a complete physical-layer trans- ceiver for 100base-tx and 10base-t applica- tions. it provides a physical coding sub-layer for communication with an external mac (media ac- cess controller), a complete physical medium at- tachment layer, and a 100base-tx and 10base- t physical medium dependent layer. high performance analog the highly integrated mixed-signal design of the CS8952T eliminates the need for external analog circuitry such as transmit or receive filters. the CS8952T builds upon cirrus logics experience in pioneering the high-volume manufacturing of 10base-t integrated circuits with true internal filters. the CS8952T, cs8920, cs8904, and cs8900 include fifth-order, continuous-time but- terworth 10base-t transmit and receive filters, al- lowing those products to meet 10base-t wave shape, emission, and frequency content require- ments without external filters. low power consumption the CS8952T is implemented in low power cmos, consuming only 135 ma typically. three low-power modes are provided to make the CS8952T ideal for power sensitive applications. application flexibility the CS8952Ts digital interface and operating modes can be tailored to efficiently support a wide variety of applications. for example, the media in- dependent interface (mii) supports 100base-tx and 10base-t nic cards, switches and routers. additionally, the low-latency repeater interface mode minimizes data delay through the CS8952T, facilitating system compliance with overall net- work delay budgets. to support 10base-t appli- cations, the CS8952T provides a 10base-t serial port (seven-wire endec interface). typical connection diagram figure 1 illustrates a typical mii to CS8952T appli- cation with twisted-pair interfaces. refer to the de- sign considerations section for detailed information on power supply requirements and de- coupling, crystal and magnetics requirements, and twisted-pair transceiver connections.
ds206pp3 5 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook vss res vss 4.99k w xtal_i xtal_o mdio 33 w mdc txd[3:0] tx_er/txd[4] tx_en tx_clk rx_clk rxd[3]/phyad[3] rx_er/rxd[4]/phyad[4] rx_dv/mii_drv col/phyad0 crs/phyad[2] 4 mii interface speed10 speed100 led1 led2 led3 led4 led5 vdd vdd_mii vdd_mii vdd 10f 0.1f rsvd vss test0 test1 an0 an1 nc nc cs8952 rx_en pwrdn repeater bp4b5b bpalign lpbk isodef 10bt_ser reset mii_irq control interface lpstrt tcm txslew0 txslew1 nc nc 1.5k w vdd_mii rxd[2] rxd[1]/phyad[1] rxd[0] vdd_mii 4.7k w 680 w vdd_mii + 3 3 11 11 10f 0.1f + 25mhz 49.9 w 0.1f tx+ tx- rx+ rx- 1 2 3 4 5 6 7 8 rj-45 shld shld 7 transformer 5 1% 49.9 w 1% 0.1f 75 w 75 w 0.01f 2kv 51 w 51 w 51 w 51 w 51 w 51 w 680 w 680 w 680 w 680 w 680 w 680 w 4.7k w 4.7k 33 w 33 w 33 w 33 w 33 w 33 w 33 w 33 w 33 w nc 1% 19 7 10v 10v figure 1. typical connection diagram
6 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook pin descriptions pin diagram vss vdd vss nc nc nc nc nc nc vss vdd vss vss rx_en reset repeater clk25 vss vdd vss vdd_mii vss 10bt_ser test0 test1 rsvd rsvd led5 led4 led3 led2 led1 spd10 spd100 vdd_mii vss pwrdn isodef vss txslew1 txslew0 tcm an1 an0 bp4b5b vss vdd vss bpalign lpbk mii_irq mdio mdc rxd2 rxd1/phyad1 rxd0 rx_dv/mii_drv vdd_mii vss rx_clk rx_er/rxd4/phyad4 tx_er/txd4 vss vdd vss tx_clk tx_en txd0 txd1 txd2 txd3 col/phyad0 crs/phyad2 lpstrt vdd rsvd rsvd xtal_o xtal_i vss vdd vss rx- rx+ vss vdd vdd vss res vss rsvd vss vdd tx- tx+ vdd vss rsvd rsvd 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 rxd3/phyad3 cs8952 100-pin tqfp (14 mm x 14 mm)
ds206pp3 7 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook mii interface pins col/phyad0 - collision detect/phy address 0. input/tri-state output, pin 48. asserted active-high to indicate a collision on the medium during half-duplex operation. in full-duplex operation, col is undefined and should be ignored. when configured for 10 mb/s operation, col is also used to indicate a signal quality error (sqe) condition. at power-up or at reset, the logic value on this pin is latched into bit 0 of the phy address field of the self status register (address 19h). this pin includes a weak internal pull-down (~ 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. note: silicon revisions a and b included a weak internal pull-up rather than a pull-down. crs/phyad2 - carrier sense/phy address 2. input/tri-state output, pin 49. the operation of crs is controlled by the repeater pin as follows: at power-up or at reset, the logic value of this pin is latched into bit 2 of the phy address field of the self status register (address 19h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. mdc - management data clock. input, pin 28. input clock used to transfer serial data on mdio. the maximum clock rate is 16.67 mhz. this clock may be asynchronous to rx_clk and tx_clk. mdio - management data input/output. bi-directional, pin 27. bi-directional signal used to transfer management data between the CS8952T and the ethernet controller. in order to conform with annex 22b of the ieee 802.3u specification, the mii_drv pin should be pulled high during power-up or reset, and the mdio pin should have an external 1.5 k w pull-up resistor. mii_irq - mii interrupt. open drain output, pin 26. asserted low to indicate the status corresponding to one of the unmasked interrupt status bits in the interrupt status register (address 11h) has changed. it will remain low until the isr is read, clearing all status bits. this open drain pin requires a 4.7 k w pull-up resistor. repeater pin duplex mode crs indicates high dont care receive activity only low full duplex receive activity only low half duplex receive or transmit activity
8 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook rx_clk - receive clock. tri-state output, pin 36 continuous clock output used as a reference clock for sampling rxd[3:0], rx_er, and rx_dv. rx_clk will have the following nominal frequency: in order to conform with annex 22b of the ieee 802.3u specification, the mii_drv pin should be pulled high during power-up or reset, and the rx_clk pin should have an external 33 w series resistor. for systems not required to drive external connectors and cables as described in the ieee802.3u specification, the external series resistor may not be necessary. rx_dv/mii_drv - receive data valid/mii drive strength. input/tri-state output, pin 33. asserted high to indicate valid data nibbles are present on rxd[3:0]. at power-up or at reset, this pin is used as an input to determine the drive strength of the mii output drivers. when the pin is low, all mii output drivers will be standard 4 ma cmos drivers. when high, additional drive strength will be added to the mii output drivers. this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. in order to conform with annex 22b of the ieee 802.3u specification, this pin should be pulled high during power-up or reset and should have an external 33 w series resistor. for systems not required to drive external connectors and cables as described in the ieee802.3u specification, it may be possible to reduce overall power consumption by pulling the pin low at power-up or reset, and the external series resistor may not be necessary. rx_en - receive enable. input, pin 14. when high, signals rxd[3:0], rx_clk, rx_dv, and rx_er are enabled. when low, these signals are tri-stated. rx_en allows the received data signals of multiple phy transceivers to share the same mii bus. this pin includes a weak internal pull-up (> 150 k w ), or the value may be set by an external 10 k w pull-up or pull-down resistor. rx_er/phyad4/rxd4 - receive error/phy address 4/receive data 4. input/tri-state output, pin 37. during normal mii operation, this pin is defined as rx_er (receive error). when rx_dv is high, rx_er asserted high indicates that an error has been detected in the current receive frame. when rx_dv is low and rxd[3:0] = 1110, rx_er high indicates a false carrier condition. speed 10bt_ser pin nominal frequency 100 mb/s n/a 25 mhz 10 mb/s low (parallel) 2.5 mhz 10 mb/s high (serial) 10 mhz
ds206pp3 9 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook if either bpalign or bp4b5b is asserted, then this pin is re-defined as rxd4 (receive data 4), the most-significant bit of the received five-bit code-group. if the 4b5b encoder is being bypassed, receive data is present when rx_dv is asserted. if alignment is being bypassed, data reception is continuous. at power-up or at reset, the logic value on this pin is latched into bit 4 of the phy address field of the self status register (address 19h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. in order to conform with annex 22b of the ieee 802.3u specification, the mii_drv pin should be pulled high during power-up or reset, and the rx_er pin should have an external 33 w series resistor. for systems not required to drive external connectors and cables as described in the ieee802.3u specification, the external series resistor may not be necessary. rxd3/phyad3 - receive data 3/phy address 3. input/tri-state output, pin 29. rxd2 - receive data 2. tri-state output, pin 30. rxd1/phyad1 - receive data 1/phy address 1. input/tri-state output, pin 31. rxd0 - receive data 0. tri-state output, pin 32. receive data output. receive data is present when rx_dv is asserted. rxd0 is the least- significant bit. for mii modes, nibble-wide data (synchronous to rx_clk) is transferred on pins rxd[3:0]. in 10 mb/s serial mode, pin rxd0 is used as the serial output pin, and rxd[3:1] are ignored. when either bp4b5b or bpalign is selected, pin rxd4 contains the most-significant bit of the five-bit code-group. at power-up or at reset, the value on rxd1/phyad1 is latched into bit 1 of the phy address field of the self status register (address 19h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. at power-up or at reset, the logic value on rxd3/phyad3 is latched into bit 3 of the phy address field of the self status register (address 19h). this pin includes a weak internal pull- down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. in order to conform with annex 22b of the ieee 802.3u specification, the mii_drv pin should be pulled high during power-up or reset, and the rxd[3:0] pins should have external 33 w series resistors. for systems not required to drive external connectors and cables as described in the ieee802.3u specification, the external series resistors may not be necessary. tx_clk - transmit clock. input/tri-state output, pin 42. continuous clock signal used by the CS8952T as a reference clock to sample txd[3:0], tx_er, and tx_en. tx_clk can be referenced either internally (output mode) or externally (input mode) based upon the value of the tcm pin at power-up or at reset. tcm pin tx_clk mode clk25 status high tx_clk is input clk25 pin is an output floating tx_clk is input clk25 is disabled low tx_clk is output clk25 is disabled
10 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook when the tcm pin is high on power-up or reset, the clk25 pin may be used as a source for the tx_clk pin. when the tcm pin is floating on power-up or reset, tx_clk must be supplied externally. tx_clk should have the following nominal frequency: tx_en - transmit enable. input, pin 43. asserted high to indicate valid data nibbles are present on txd[3:0]. when bpalign is selected, tx_en must be pulled up to vdd_mii. tx_er/txd4 - transmit error encoding/transmit data 4. input, pin 38. when high, tx_er indicates to the CS8952T that a transmit error has occurred. if tx_er is asserted simultaneously with tx_en in 100 mb/s mode, the CS8952T will ignore the data on the txd[3:0] pins and transmit one or more 100 mb/s halt symbols in its place. in 10 mb/s mode, tx_er has no effect on the transmitted data. if bp4b5b or bpalign are set, tx_er/txd4 is used to transmit the most-significant bit of the five-bit code group. txd[3:0] - transmit data. input, pins 47, 46, 45, and 44. transmit data input pins. for mii modes, nibble-wide data (synchronous to tx_clk) must be presented on pins txd[3:0] when tx_en is asserted high. txd0 is the least significant bit. in 10 mb/s serial mode, pin txd0 is used as the serial input pin, and txd[3:1] are ignored. when either bp4b5b or bpalign is selected, pin txd4 contains the most significant bit of the five-bit code-group. control and status pins 10bt_ser - 10 mb/s serial mode select. input, pin 23. when asserted high during power-up or reset and 10 mb/s operation is selected, serial data will be transferred on pins rxd0 and txd0. when low during power-up or reset and 10 mb/s operation is selected, data is transferred a nibble at a time on rxd[3:0] and txd[3:0]. this pin is ignored during 100 mb/s operation. 10 mb/s serial mode may also be entered under software control through bit 9 of the 10base- t status register (address 1bh). at power-up or at reset, the value on this pin is latched into bit 9 of the 10base-t status register (address 1bh). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. speed 10bt_ser pin nominal frequency 100 mb/s low (nibble) 25 mhz 10 mb/s low (nibble) 2.5 mhz 10 mb/s high (serial) 10 mhz
ds206pp3 11 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook an[1:0] - auto-negotiate control. input, pins 58 and 57. these three-level input pins are sampled during power-up or reset. they control the forced or advertised auto-negotiation operating modes. if either of these pins is left unconnected, internal logic pulls its signal to a mid-range value, designated as 'm' in the following table. either pin may also be connected to a 5 to 25 mhz ttl-level clock source, designated as c in the following table. a minimum of 8 rising edges of the clock are required while reset is asserted for the an[1:0] input logic to interpret the input as c. auto-negotiation may also be enabled and the advertised capabilities modified under software control through bit 8 of the basic mode control register (address 00h), and bits 5, 6, 7, 8, and 10 of the auto-negotiation advertisement register (address 04h). these pins are pulled to m through weak internal resistors (> 150 k w ). other values may be set by tying them directly to vdd_mii, vss, or a clock source, or through external 10 k w pull-up or pull-down resistors. bp4b5b - bypass 4b5b coders. input, pin 56. when driven high during power-up or reset, the transmit 4b5b encoder and receiver 5b4b decoder are bypassed. five-bit code groups are output and input on pins rxd[4:0] and txd[4:0]. the 4b5b coders may also be bypassed under software control through bit 14 of the loopback, bypass, and receiver error mask register (address 18h). an1 pin an0 pin forced/auto speed full/half duplex 0 m forced 10 mb/s half 1 m forced 10 mb/s full m 0 forced 100 mb/s half m 1 forced 100 mb/s full c m forced 100 mb/s full (note 1) 1. the auto-negotiation advertisement register will be modified to advertise 100 mb/s full/half. m c forced 100 mb/s full (note 2) 2. the auto-negotiation advertisement register will be modified to advertise 100/10 mb/s full. c c forced 100 mb/s half (note 3) 3. the auto-negotiation advertisement register will be modified to advertise 100/10 mb/s half. m m auto-neg 100/10 mb/s full/half 0 0 auto-neg 10 mb/s half 0 1 auto-neg 10 mb/s full 1 0 auto-neg 100 mb/s half 1 1 auto-neg 100 mb/s full c 1 auto-neg 100/10 mb/s full c 0 auto-neg 100/10 mb/s half 1 c auto-neg 100 mb/s full/half 0 c auto-neg 10 mb/s full/half
12 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook at power-up or at reset, the value on this pin is latched into bit 14 of the loopback, bypass and receiver error mask register (address 18h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. bpalign - bypass symbol alignment. input, pin 52. when driven high during power-up or reset, the following blocks are bypassed: 4b5b encoder, 5b4b decoder, scrambler and descrambler. five-bit code groups are output and input on pins rxd[4:0] and txd[4:0]. the receiver will output five-bit data with no attempt to identify code-group boundaries; therefore, the data in one rxd[4:0] word may contain data from two code groups. symbol alignment may also be bypassed under software control through bit 12 of the loopback, bypass, and receiver error mask register (address 18h). at power-up or at reset, the value on this pin is latched into bit 12 of the loopback, bypass and receiver error mask register (address 18h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. isodef - isolate default. input, pin 63. when asserted high during power-up or reset, the mii will power-up electrically isolated except for the mdio and mdc pins. when low, the part will exit reset fully electrically connected to the mii. the mii may also be isolated under software control through bit 10 of the basic mode control register (address 00h). at power-up or at reset, the value on this pin is latched into bit 10 of the basic mode control register (address 00h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. led1 - transmit active led. open drain output, pin 69. this active-low output indicates transmit activity. it contains a pulse stretcher to insure that the transmit events are visible when the pin is used to drive an led. the definition of this pin may be modified to indicate disconnect detection (bit 5 of the self status register (address 19h)) by setting bit 2 of the pcs sub-layer configuration register (address 17h). this pin can be simultaneously connected to an led and to a ttl-compatible, cmos input pin. led2 - receive activity led. open drain output, pin 70. this active-low output indicates receive activity. it contains a pulse stretcher to insure that the receive events are visible when the pin is used to drive an led. this pin can be simultaneously connected to an led and to a ttl-compatible, cmos input pin.
ds206pp3 13 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook led3 - link good led. open drain output, pin 71. this active-low output indicates the CS8952T has detected a valid link. this pin can be simultaneously connected to an led and to a ttl-compatible, cmos input pin. led4 - polarity/full duplex led. open drain output, pin 72. this active-low output indicates: 1) for 100 mb/s operation, the CS8952T is in full-duplex operation, 2) for 10 mb/s operation, either good polarity exists or full duplex is selected (see bit 1 in the pcs sub-layer configuration register (address 17h)). this pin can be simultaneously connected to an led and to a ttl-compatible, cmos input pin. led5 - collision/descrambler lock led. open drain output, pin 73. this active-low output is asserted when either the CS8952T detects a collision (bit 11 of the pcs sub-layer configuration register (address 17h) is clear), or the 100base-tx descrambler is synchronized (bit 11 of the pcs sub-layer configuration register (address 17h) is set). it contains a pulse stretcher to insure that the collision events are visible when the pin is used to drive an led. this pin can be simultaneously connected to an led and to a ttl-compatible, cmos input pin. lpbk - loopback enable. input, pin 51. when this pin is asserted high and the CS8952T is operating in 100 mb/s mode, the CS8952T will perform a local loopback inside the pmd block. the loopback includes all CS8952T 100 mb/s functionality except the mlt-3 coders and the analog line interface blocks. when asserted high and the CS8952T is operating in 10 mb/s mode, the CS8952T will perform a local endec loopback. lpstrt - low power start. input, pin 50. when this active-low input is asserted during power-up or reset, the CS8952T will exit reset in a low power configuration, where the only circuitry enabled is that necessary to maintain the media impedance. the CS8952T will remain in a low power state until reset pin is asserted or the mdc pin toggles. this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor.
14 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook pwrdn - power down. input, pin 64. when this pin is asserted high, the CS8952T powers down all circuitry except that circuitry needed to maintain the network line impedance. this is the lowest power mode possible. the CS8952T will remain in low power mode until the pwrdn pin is deasserted. a slightly higher power power-down mode may also be entered under software control through bit 11 of the basic mode control register (address 00h). repeater - repeater mode select. input, pin 16. this pin controls the operation of the crs (carrier sense) pin as shown below: at power-up or at reset, the value on this pin is latched into bit 12 of the pcs sub-layer configuration register (address 17h). this pin includes a weak internal pull-down (> 20 k w ), or the value may be set by an external 4.7 k w pull-up or pull-down resistor. spd10 - 10 mb/s speed indication. output, pin 68. this pin is asserted high when the CS8952T is configured for 10 mb/s operation. this pin can be used to drive a low-current led to indicate 10 mb/s operation. spd100 - 100 mb/s speed indication. output, pin 67. this pin is asserted high when the CS8952T is configured for 100 mb/s operation. this pin can be used to drive a low-current led to indicate 100 mb/s operation. tcm - transmit clock mode initialization. input, pin 59. the logic value on this three-level pin during power-up or reset determines whether tx_clk is used as an input or an output, and whether an external 25 mhz clock reference is provided on the clk25 output pin. test[1:0] - factory test. input, pins 24 and 25. these pins are for factory test only. they include weak internal pull-downs (> 20 k w ), and should be tied directly to vss for normal operation. repeater pin duplex mode crs indicates high dont care receive activity only low full duplex receive activity only low half duplex receive or transmit activity tcm pin tx_clk mode clk25 status high tx_clk is input clk25 pin is an output floating tx_clk is input clk25 is disabled low tx_clk is output clk25 is disabled
ds206pp3 15 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook txslew[1:0] - transmit slew rate control. input, pins 61 and 60. these three-level pins allow adjustment to the rise and fall times of the 100base-tx transmitter output waveform. the rise and fall times are symmetric. media interface pins rx+, rx- - 10/100 receive. differential input pair, pins 91 and 92. differential input pair receives 10 or 100 mb/s data from the receive port of the transformer primary. tx+, tx- - 10/100 transmit. differential output pair, pins 80 and 81. differential output pair drives 10 or 100 mb/s data to the transmit port of the transformer primary. general pins clk25 - 25 mhz clock. tristate output, pin 17. a 25 mhz clock is output on this pin when the CS8952T is configured to use an external reference transmit clock in tx_clk in master mode. see the pin description for the transmit clock mode initialization pin (tcm) for more information on tx_clk operating modes. clk25 may also be enabled regardless of the tcm pin state by clearing bit 7 of the pcs sub- layer configuration register (address 17h). res - reference resistor. input, pin 86. this input should be connected to ground with a 4.99 k w +/-1% series resistor. the resistor is needed for the biasing of internal analog circuits. txslew0 pin txslew1 mode rise/fall time low low 0.5 ns low floating 1.0 ns low high 1.5 ns floating low 2.0 ns floating floating 2.5 ns floating high 3.0 ns high low 3.5 ns high floating 4.0 ns high high 4.5 ns
16 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook reset - reset. input, pin 15. this active high input initializes the CS8952T, and causes the CS8952T to latch the input signal on the following pins: col/phyad0, crs/phyad2, rx_er/phyad4/rxd4, 10bt_ser, bp4b5b, bpalign, bpscr, isodef, repeater, rxd1/phyad1, and rxd3/phyad3. xtal_i - crystal input, pin 96. xtal_o - crystal output, pin 97. a 25 mhz crystal should be connected across pins xtal_i and xtal_o. if a crystal is not used, a 25 mhz cmos level clock may be connected to xtal_i and xtal_o left open. note: the xtal_i pin capacitive load may be as high as 35pf. any external clock source connected to this pin must be capable of driving larger capacitive loads. rsvd - reserved. pins 74, 75, 76, 77, 84, 98, and 99. these seven pins are reserved and should be tied to vss. vdd_mii - i/o pad power. pins 21, 34, and 66. these pins provide power to all CS8952T digital i/o pads. typically vdd_mii will be either +5v or +3.3v. vdd - core power. pins 2, 11, 19, 40, 54, 79, 82, 88, 89, 94, and 100. these pins provide power to the CS8952T core. typically, vdd should be +5v. vss - pins 1, 3, 10, 12, 13, 18, 20, 22, 35, 39, 41, 53, 55, 62, 65, 78, 83, 85, 87, 90, 93, and 95. these pins provide a ground reference for the CS8952T.
ds206pp3 17 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook functional description digital system interface the primary digital interface to the CS8952T is an enhanced ieee 802.3 media independent interface (mii). the mii supports parallel data transfer, ac- cess to the CS8952T control and status registers, and several status and control pins. for 100base-x applications, the digital data in- terface can be either 4-bit parallel (nibbles) or 5-bit parallel (symbols). for 10base-t applications, the digital data format can be either 4-bit parallel (nibbles) or one-bit serial. while the CS8952T can be fully controlled through configuration registers via the mii management interface, most fundamental functions can be set at power-up and reset time through external pins. major operating modes the following sections describe the four major op- erating modes of the CS8952T: - 100base-tx nibble mode - 100base-x symbol modes - 10base-t nibble mode - 10base-t serial mode the digital interface mode (nibble, symbol, or seri- al) is selected through input pins 10bt_ser, bpalign and bp4b5b as shown in table 1. table 1. operating mode selection the choice of operating speed and duplex mode is made using the auto-negotiation input pins (an0, an1) and/or the auto-negotiation mii registers. both speed and duplex modes can either be forced or negotiated with the link partner as shown in table 5 on page 23. 100base-tx nibble mode in 100base-tx nibble mode, the CS8952T pro- vides an ieee 802.3-compliant mii interface. data is transferred across the mii in four-bit nibbles. tx_clk and rx_clk are nominally 25 mhz. symbol encoding and decoding four-bit nibble transmit data is encoded into five- bit symbols for transmission onto the media as shown in tables 2 and 3. while this encoding caus- es the symbol rate transmitted across the wire (125 symbols/second) to be greater than the actual data rate of the system (100 symbols/second), it is nec- essary to allow data and control symbols to be sent consecutively along the same media transparent to the mac layer. operating mode 10bt_ser bpalign bp4b5b 100base-tx nibble 10base-t nibble 000 100base-tx symbol 001 01 dont care 10base-t serial 1 dont care dont care
18 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook table 2. 4b5b symbol encoding/decoding data and control codes (rx_er = 0 or tx_er = 0) name 5-bit symbol 4-bit nibble comments data (note 1) 0 11110 0000 1 01001 0001 2 10100 0010 3 10101 0011 4 01010 0100 5 01011 0101 6 01110 0110 7 01111 0111 8 10010 1000 9 10011 1001 a 10110 1010 b 10111 1011 c 11010 1100 d 11011 1101 e 11100 1110 f 11101 1111 control (note 2) i 11111 0101 idle (note 3) j 11000 0101 first start of stream symbol k 10001 0101 second start of stream symbol t 01101 0000 first end of stream symbol r 00111 0000 second end of stream symbol 1. data code groups are indicated by rx_dv = 1 2. control code groups are inserted automatically during transmission in response to tx_en. they are not generated through any combination of txd[3:0] or tx_er. 3. idle is indicated by rx_dv = 0.
ds206pp3 19 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook table 3. 4b5b code violation decoding carrier sense operation the crs pin (carrier sense) is asserted when ei- ther the transmitter is active or the receiver detects at least two non-contiguous zeros within any 10 bits in the received data stream. once asserted, it will remain asserted until the transmitter has gone idle or the receiver detects 10 consecutive ones. crs is not synchronous to rx_clk. it may tran- sition at any time. link integrity monitor the link integrity monitor determines whether the underlying receive channel is providing reliable data. when auto-negotiation is disabled, the link is con- sidered to be stable when the receiver has detected valid signal levels for at least 1 ms. if the signal levels fall below the minimum for more than 350 us, the link status bit in the basic mode status register (address 01h) is cleared, the link status change bit in the interrupt status register (address 11h) is set, and the disconnect count register (ad- dress 12h) is incremented. when auto-negotiation is enabled, the link will be further qualified by the detection 100base-x mode and 12 consecutive idle code groups. collision detection for half duplex, a collision is detected when the re- ceiver and transmitter are active simultaneously. collisions are reported by asserting the col pin. code violations (rx_er = 1 or tx_er = 1) name 5-bit symbol normal mode 4-bit nibble error report mode 4-bit nibble comments control (note 1) 1. control code groups become violations when found in the data portion of the frame. i 11111 0000 0000 this portion of the table relates received 5-bit symbols to received 4-bit nibbles only. the control code groups may not be transmitted in the data portion of the frame. j 11000 0000 0000 k 10001 0000 0000 t 01101 0000 0000 r 00111 0000 0000 code violations h 00100 0000 0000 v0 00000 0110 or 0101 (note 2) 2. invalid code groups are mapped to 5h unless the code error report select bit in the loopback, bypass, and receiver error mask register (address 18h) is set, in which case invalid code groups are mapped to 6h. 0001 v1 00001 0110 or 0101 (note 2) 0111 v2 00010 0110 or 0101 (note 2) 1000 v3 00011 0110 or 0101 (note 2) 1001 v4 00101 0110 or 0101 (note 2) 1010 v5 00110 0110 or 0101 (note 2) 1011 v6 01000 0110 or 0101 (note 2) 1100 v7 01100 0110 or 0101 (note 2) 1101 v8 10000 0110 or 0101 (note 2) 1110 v9 11001 0110 or 0101 (note 2) 1111
20 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook col is not synchronous to rx_clk. it may tran- sition at any time. false carrier detection a false carrier condition is detected when the re- ceiver has asserted crs but a valid /j/k code group sequence is not received. when this condition is detected, the CS8952T will assert rx_er and place 1110 on the rxd[3:0] pins until either the receiver detects at least two consecutive idle code groups. in addition, the false carrier count register (address 13h) will be incremented. 100 mb/s loopback the CS8952T includes two 100 mb/s loopback modes. local loopback redirects the txd[3:0] input data to rxd[3:0] data outputs through the 4b5b coders and scramblers. local loopback is selected by as- serting pin lpbk, by setting the lpbk bit (bit 14) in the basic mode control register (address 00h) or by setting bits 8 and 11 in the loopback, bypass, and receiver error mask register (address 18h) as shown in table 4. remote loopback redirects the analog line interface inputs to the analog line driver outputs. remote loopback is selected by setting bit 9 in the loop- back, bypass, and receiver error mask register (address 18h) as shown in table 4. table 4. loopback mode selection when changing between local and non-loopback modes, the data on rxd[3:0] will be undefined for approximately 330 s. 100base-x symbol modes the CS8952T provides two low latency modes for 100base-x repeater applications. these are se- lected by asserting either pin bpalign or bp4b5b. both pins have the effect of bypassing the 4b5b encoder and decoder. bypassing the cod- ers decreases latency, and uses a 5-bit wide parallel code group interface on pins rxd[4:0] and txd[4:0] instead of the 4-bit wide mii nibble in- terface on pins rxd[3:0] and txd[3:0]. in repeat- er mode, pin rx_er is redefined as the fifth receive data bit (rxd4), and pin tx_er is rede- fined as the fifth transmit data bit (txd4). bpalign can also be selected by setting bit 12 in loopback, bypass, and receiver error mask reg- ister (address 18h). bp4b5b can be selected by set- ting bit 14 of the same register. pin bpalign causes more of the CS8952T to be bypassed than the bp4b5b pin. bpalign also bypasses the scrambler/descrambler (see figure 1). asserting the repeater pin or setting bit 12 in the pcs sublayer configuration register (address 17h) redefines the function of the crs (carrier sense) pin to be asserted only on receive activity. the repeater pin is also used to enable the car- rier integrity monitor feature by default. for repeater applications, the rx_en pin can be used to gate the receive data pins (rxd[4:0], rx_clk, rx_dv, col, and crs) onto a shared, external repeater system bus. carrier integrity monitor the carrier integrity monitor function allows a re- peater to protect the attached network from some transient fault conditions that would disrupt net- work communications. the CS8952T contains a self-interrupt capability to prevent a segments remote loopback (bit 9) pmd loopback (bit 8) function 0 0 no loopback 0 1 local loopback (toward mii) 1 0 remote loopback (toward line) 1 1 operation is undefined
ds206pp3 21 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook spurious carrier activity from propagating through the repeater to other attached segments. the false carrier detection logic described earlier is used to increment a false carrier counter. when two consecutive false carrier events are detected, the CS8952T will deassert the link ok bit in the self status register (address 19h), set the link status change bit in the interrupt status register (address 11h), increment the disconnect count register (address 12h), stop propagating received data to the mii, and ignore any transmit data from the mii. the receiver will continue to monitor the received data stream for valid idle symbols. once dis- abled, the receiver and transmitter will remain dis- abled until the link integrity monitor has determined the link has again stabilized. the carrier integrity monitor may be disabled through the cim disable bit in the pcs sub-layer configuration register (address 17h). it is enabled by default when the repeater pin is asserted on reset or power-up. 10base-t mii application the digital interface used in this mode is the same as that used in the 100base-x nibble modes ex- cept that tx_clk and rx_clk are nominally 2.5 mhz. the CS8952T includes a full-featured 10base-t interface, as described in the following sections. duplex operation the CS8952T supports both 10base-t full and half duplex operation as determined by pins an[1:0] and/or the corresponding mii register bits. (see table 5 on page 23). carrier detection the carrier detect circuit informs the mac that valid receive data is present by asserting the carrier sense signal (crs) as soon it detects a valid bit pattern (1010b or 0101b for 10base-t). during normal packet reception, crs remains asserted while the frame is being received, and is de-assert- ed within 2.3 bit times after the last low-to-high transition of the end-of-frame (eof) sequence. whenever the receiver is idle (no receive activity), crs is de-asserted. collision detection if half duplex operation is selected, the CS8952T detects a 10base-t collision whenever the receiv- er and transmitter are active simultaneously. when a collision is present, the collision is reported on pin col. collision detection is undefined for full-duplex op- eration. jabber the jabber timer monitors the transmitter and dis- ables the transmission if the transmitter is active for greater than approximately 105 ms. the transmit- ter stays disabled until approximately 406 ms after the internal transmit request is no longer enabled. link test pulses to prevent disruption of network operation due to a faulty link segment, the CS8952T continually monitors the 10base-t receive pair (rxd+ and rxd-) for packets and link pulses. after each packet or link pulse is received, an internal link- loss timer is started. as long as a packet or link pulse is received before the link-loss timer finish- es (between 50 and 100 ms), the CS8952T main- tains normal operation. if no receive activity is detected, the CS8952T disables packet transmis- sion to prevent blind transmissions onto the net- work (link pulses are still sent while packet transmission is disabled). to reactivate transmis- sion, the receiver must detect a single packet (the packet itself is ignored), or two normal link pulses separated by more than 6 ms and no more than 50 ms. in the absence of transmit packets, the transmitter generates link pulses in accordance with
22 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook section 14.2.1.1 of the ethernet standard. trans- mitted link pulses are positive pulses, one bit time wide, typically generated at a rate of one every 16 ms. the 16 ms timer also starts whenever the transmitter completes an end-of-frame (eof) se- quence. thus, a link pulse will be generated 16 ms after an eof unless there is another transmitted packet. link polarity detection the CS8952T automatically checks the polarity of the receive half of the twisted pair cable. to detect a reversed pair, the receiver examines received link pulses and the end-of-frame (eof) sequence of incoming packets. if it detects at least one reversed link pulse and at least four frames in a row with negative polarity after the eof, the receive pair is considered reversed. if the polarity is reversed and the polarity disable bit of the 10base-t configuration register (ad- dress 1ch) is clear, the CS8952T automatically corrects a reversal. sqe (heartbeat) test function when sqe is enabled, the CS8952T will assert the col pin for approximately 10 bit times within 1 m s after the transmission of each packet. the sqe function is disabled by default when the repeater pin is deasserted on reset or power- up. it may be enabled through the sqe enable bit in the 10base-t configuration register (address 1ch). receiver squelch the 10base-t squelch circuit determines when valid data is present on the rxd+/rxd- pair. in- coming signals passing through the receive filter are tested by the squelch circuit. any signal with amplitude less than the squelch threshold (either positive or negative, depending on polarity) is re- jected. 10base-t loopback when loopback is selected, the txd[3:0] pins are looped back into the rxd[3:0] pins through the manchester encoder and decoder. selection is made via: - setting bit 14 in the basic mode control register (address 00h) or - setting bits 8 and 11 in the loopback, by- pass, and receiver error mask register (address 18h) or - asserting the lpbk pin. 10base-t serial application this mode is selected when pin 10bt_ser is as- serted during power-up or reset, and operates simi- lar to the 10base_t mii mode except that data is transferred serially on pins rxd0 and txd0 using a 10 mhz rx_clk and tx_clk. receive data is framed by crs rather than rx_dv. auto-negotiation the CS8952T supports auto-negotiation, which is the mechanism that allows the two devices on ei- ther end of an ethernet link segment to share infor- mation and automatically configure both devices for maximum performance. when configured for auto-negotiation, the CS8952T will detect and au- tomatically operate full-duplex at 100 mb/s if the device on the other end of the link segment also supports full-duplex, 100 mb/s operation, and auto-negotiation. the CS8952T auto-negotiation capability is fully compliant with the relevant por- tions of section 28 of the ieee 802.3u standard. the CS8952T can auto-negotiate both operating speed (10 versus 100 mb/s), duplex mode (half du- plex versus full duplex), and flow control (pause frames), or alternatively can be set not to negotiate.
ds206pp3 23 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook auto-negotiation configuration at power-up and reset times, the auto-negotiation mode is selected via the auto-negotiation input pins (an[1:0]). these three-level input pins are sam- pled during power-up or reset. if either of these pins is left unconnected, internal logic pulls its sig- nal to a mid-range value, designated as 'm' in the following table. either pin may also be connected to a 5 to 25 mhz ttl-level clock source, designat- ed as c in the following table. a minimum of 8 rising edges of the clock are required while reset is asserted for the an[1:0] input logic to interpret the input as c. auto-negotiation may also be enabled and the ad- vertised capabilities modified under software con- trol through bit 8 of the basic mode control register (address 00h), and bits 5, 6, 7, 8, and 10 of the auto-negotiation advertisement register (ad- dress 04h). auto-negotiation operation auto-negotiation encapsulates information within a burst of closely spaced link integrity test pulses, referred to as a fast link pulse (flp) burst. the flp burst consists of a series of link integrity pulses which form an alternating clock / data se- quence. extraction of the data bits from the flp burst yields a link code word which identifies the capability of the remote device. in order to support legacy 10 and 100 mb/s devic- es, the CS8952T also supports parallel detection. in parallel detection, the CS8952T monitors activity on the media to determine the capability of the link partner even without auto-negotiation having oc- curred. an1 pin an0 pin forced/auto speed full/half duplex 0 m forced 10 mb/s half 1 m forced 10 mb/s full m 0 forced 100 mb/s half m 1 forced 100 mb/s full c m forced 100 mb/s full (note 1) m c forced 100 mb/s full (note 2) c c forced 100 mb/s half (note 3) m m auto-neg 100/10 mb/s full/half 0 0 auto-neg 10 mb/s half 0 1 auto-neg 10 mb/s full 1 0 auto-neg 100 mb/s half 1 1 auto-neg 100 mb/s full c 1 auto-neg 100/10 mb/s full c 0 auto-neg 100/10 mb/s half 1 c auto-neg 100 mb/s full/half 0 c auto-neg 10 mb/s full/half table 5. auto-negotiation mode selection 1. the auto-negotiation advertisement register will be modified to advertise 100 mb/s full/half. 2. the auto-negotiation advertisement register will be modified to advertise 100/10 mb/s full. 3. the auto-negotiation advertisement register will be modified to advertise 100/10 mb/s half.
24 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook reset operation reset occurs in response to six different conditions: 1) there is a chip-wide reset whenever the re- set pin is high for at least 200 ns. during a chip-wide reset, all circuitry and registers in the CS8952T are reset. 2) when power is applied, the CS8952T main- tains reset until the voltage at the vdd supply pins reaches approximately 3.6 v. the CS8952T comes out of reset once vdd is greater than approximately 3.6 v and the crys- tal oscillator has stabilized. 3) there is a chip-wide reset whenever the re- set bit (bit 15 of the basic mode control reg- ister (address 00h)) is set. 4) digital circuitry is reset whenever bit 0 of the pcs sub-layer configuration register (ad- dress 17h) is set. analog circuitry is unaffected. 5) analog circuitry is reset and recalibrated when- ever the CS8952T enters or exits the power- down state, as requested by pin pwrdn. 6) analog circuitry is reset and recalibrated when- ever the CS8952T changes between 10 mb/s and 100 mb/s modes. after a reset, the CS8952T latches the signals on various input pins in order to initialize key registers and goes through a self configuration. this in- cludes calibrating on-chip analog circuitry. time required for the reset calibration is typically 40 ms. external circuitry may access registers internal to the CS8952T during this time. reset and calibra- tion complete is indicated when bit 15 of the basic mode control register (address 00h) is clear. led indicators the ledx , spd100, and spd10 output pins pro- vide status information that can be used to drive leds or can be used as inputs to external control circuitry. indication options include: receive activ- ity, transmit activity, collision, carrier sense, polar- ity ok, descrambler synchronization status, auto- negotiation status, speed (10 vs. 100), and duplex mode.
ds206pp3 25 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook media independent interface the media independent interface (mii) provides a simple interconnect to an external media access controller (mac). this connection may be chip to chip, motherboard to daughterboard, or a connec- tion between two assemblies attached by a limited length of shielded cable and an appropriate connec- tor. the CS8952T's mii interface is enhanced beyond ieee requirements by register extensions and the addition of pins for mii_irq , rx_en, and iso- def signals. the mii_irq pin provides an inter- rupt signal to the controller when a change of state has occurred in the CS8952T, eliminating the need for the system to poll the CS8952T for state chang- es. the rx_en signal allows the receiver outputs to be electrically isolated. the isodef pin con- trols the value of register bit isolate in the basic mode control register (address 00h) which in turn electrically isolates the CS8952T's mii data path. the mii interface uses the following pins: status pins - col - collision indication, valid only for half duplex modes. - crs - carrier sense indication serial management pins - mdio - a bi-directional serial data path - mdc - clock for mdio (16.7 mhz max) - mii_irq - interrupt indicating change in the interrupt status register (address 11h) receive data pins - rxd[3:0] - parallel data output path - rx_clk - recovered clock output - rx_dv - indicates when receive data is present and valid - rx_er - indicates presence of error in re- ceived data - rx_en - can be used to tri-state receiver output pins transmit data pins - txd[3:0] - parallel data input path - tx_clk - transmit clock - tx_en - indicates when transmit data is present and valid - tx_er - request to transmit a 100base- t halt symbol, ignored for 10base-t operation. the interface uses ttl signal levels, which are compatible with devices operating at a nominal supply voltage of either 5.0 or 3.3 volts. it is capa- ble of supporting either 10 mb/s or 100 mb/s data rates transparently. that is, all signaling remains identical at either data rate; only the nominal clock frequency is changed. mii frame structure data frames transmitted through the mii have the following format: each frame is preceded by an inter-frame gap. the inter-frame gap is an unspecified time during which no data activity occurs on the media as indi- cated by the de-assertion of crs for the receive path and tx_en for the transmit path. the preamble consists of seven bytes of 10101010. the start of frame delimiter consists of a single byte of 10101011. data may be any number of bytes. the end of frame delimiter is conveyed by the de- assertion of rx_dv and tx_en for receive and transmit paths, respectively. preamble (7 bytes) start of frame delimiter (1 byte) data end of frame delimiter
26 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook transmission and/or reception of each byte of data is done one nibble at a time in the following order: mii receive data the presence of recovered data on the rxd[3:0] bus is indicated by the assertion of rx_dv. rx_dv will remain asserted from the beginning of the preamble (or start of frame delimiter if pream- ble is not used) to the end of frame delimiter. once rx_dv is asserted, valid data will be driven onto rxd[3:0] synchronously with respect to rx_clk. receive errors are indicated during frame reception by the assertion of rx_er. it indicates that an er- ror was detected somewhere in the frame currently being transferred across the mii. rx_er will tran- sition synchronously with respect to the rx_clk, and will be held high for one cycle for each error received. it is up to the mac to ensure that a crc error is detected in that frame by the logical link control. figure 2 illustrates reception without er- rors, and figure 3 illustrates reception with errors. mii transmit data tx_en is used by the mac to signal to the CS8952T that valid nibbles of data are being pre- sented across the mii via txd[3:0]. tx_en must be asserted synchronously with the first nibble of preamble, and must remain asserted as long as val- id data is being presented to the mii. tx_en must be de-asserted within one tx_clk cycle after the last nibble of data (crc) has been presented to the CS8952T. when tx_en is not as- serted, data on txd[3:0] is ignored. mii lsb msb d0 d1 d2 d3 nibble stream d0 macs serial bit stream first bit first second nibble nibble d1 d2 d3 d4 d5 d6 d7 lsb msb rx_clk rx_dv rxd[3:0] rx_er preamble sfd sfd data data data data data crc figure 2. reception without errors rx_clk rx_dv rxd[3:0] rx_er preamble sfd sfd data data data error xx xx xx figure 3. reception with errors
ds206pp3 27 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook transmit errors should be signaled by the mac by asserting tx_er for one or more tx_clk cycles. tx_er must be synchronous with tx_clk. this will cause the CS8952T to replace the nibble with a halt symbol in the frame being transmitted. this invalid data will be detected by the receiving phy and flagged as a bad frame. figure 4 illus- trates transmission without errors, and figure 5 il- lustrates transmission with errors. mii management interface the CS8952T provides an enhanced ieee 802.3 mii management interface. the interface consists of three signals: a bi-directional serial data line (mdio), a data clock (mdc), and an optional in- terrupt signal (mii_irq ). the management inter- face can be used to access status and control registers internal to the CS8952T. the CS8952T implements an extended set of 16-bit mii registers. eight of the registers are defined by the ieee 802.3 specification, while the remaining registers provide enhanced monitoring and control capabilities. as many as 31 devices may share a single manage- ment interface. a unique five-bit phy address is associated with each device, with all devices re- sponding to phy address 00000. the CS8952T de- termines its phy address at power-up or reset through the phyad[4:0] pins. mii management frame structure frames transmitted through the mii management interface have the format shown in table 6 on page 28. when the management interface is idle, the mdio signal will be tri-stated, and the mac is required to keep mdio pulled to a logic one. at the beginning of each transaction, the mac will typically send a sequence of 32 contiguous logic one bits on mdio with 32 corresponding clock cycles on mdc to provide the CS8952T with a pat- tern that it can use to establish synchronization. optionally, the CS8952T may be configured to op- tx_clk tx_en txd[3:0] tx_er preamble data data data data data data data crc figure 4. transmission without errors tx_clk tx_en txd[3:0] tx_er preamble data data data xx data figure 5. transmission with errors
28 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook erate without the preamble through bit 9 of the pcs sub-layer configuration register (address 17h). table 6. mii management interface frame format the start of frame is indicated by a 01 bit pattern. a read transaction is indicated by an opcode of 10 and a write by 01. the phy address is five bits, with the most signif- icant bit sent first. if the phy address included in the frame is not 00000 or does not match the phy- ad field of the self status register (address 19h), the rest of the frame is ignored. the register address is five bits, with the most sig- nificant bit sent first, and indicates the CS8952T register to be written to/read from. the turnaround time is a two bit time spacing be- tween when the mac drives the last register ad- dress bit onto mdio and the data field of a management frame in order to avoid contention during a read transaction. for a read transaction, the mac should tri-state the mdio pin beginning on the first bit time, and the CS8952T will begin driving the mdio signal to a logic zero during the second bit time. during write transactions, since the mdio direction does not need to be re- versed, the mac will drive the mdio to a logic one for the first bit time and a logic zero for the second. the data field is always 16 bits in length, with the most significant bit sent first. preamble (32 bits) start of frame (2 bits) opcode (2 bits) phy address (5 bits) register address (5 bits) turnaround (2 bits) data (16 bits) idle
ds206pp3 29 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook configuration the CS8952T can be configured in a variety of ways. all control and status information can be ac- cessed via the mii serial management interface. additionally, many configuration options can be set at power-up or reset times via individual control lines. some configuration capabilities are available at any time via individual control lines. configuration at power-up/reset time at power-up and reset time, the following pins are used to configure the CS8952T. table 7. reset configuration pins configuration via control pins the following pins are for dedicated control signals and can be used at any time to configure the CS8952T. table 8. dedicated control pins configuration via the mii the CS8952T supports configuration by software control through the use of 16-bit configuration and status registers accessed via the mdio/mdc pins (mii management interface). the first seven regis- ters are defined by the ieee 802.3 specification. additional registers extend the register set to pro- vide enhanced monitoring and control capabilities. pin name function 10bt_ser select 10base-t serial mode an[1:0] select auto-negotiation mode bp4b5b bypass 4b5b coders bpalign bypass 4b5b coders and scramblers isodef electrically isolate mii after reset lpstrt start in low power mode phyad[4:0] set mii phy address repeater control definition of crs pin, enable carrier integrity monitor and sqe func- tion mii_drv set mii driver strength tcm set tx_clk mode txslew[1:0] set 100base-tx transmitter output slew rate pin name function lpbk enter loopback mode pwrdn enter power-down mode reset reset
30 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook CS8952T registers the CS8952T register set is comprised of the 16- bit status and control registers described below. a detailed description each register follows. table 9. CS8952T register set register address description type 0h basic mode control register read/write 1h basic mode status register read-only 2h phy identifier #1 read-only 3h phy identifier #2 read-only 4h auto-negotiation advertisement register read/write 5h auto-negotiation link partner ability register read-only 6h auto-negotiation expansion register read-only 7h auto-negotiation next page transmit register read/write 8h through fh reserved by ieee 802.3 working group - 10h interrupt mask register read/write 11h interrupt status register read-only 12h disconnect count register read-only 13h false carrier count register read-only 14h scrambler key initialization register read/write 15h receive error count register read-only 16h descrambler key initialization register read/write 17h pcs sub-layer configuration register read/write 18h loopback, bypass and receiver error mask register read/write 19h self-status register read/write 1ah reserved - 1bh 10base-t status register read-only 1ch 10base-t configuration register read/write 1dh through 1fh reserved -
ds206pp3 31 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook basic mode control register - address 00h 15 14 13 12 11 10 9 8 software reset loopback speed selection auto-neg enable power down isolate restart auto-neg duplex mode 7 6 5 4 3 2 1 0 collision test reserved bit name type reset description 15 software reset read/set 0 setting this bit performs a chip-wide reset. all status and control registers are set to their default states, and the analog circuitry is re-calibrated. this bit is an act-once bit which is cleared once the reset and re- calibration have completed. this bit will also be set automatically while the analog circuitry is reset and re-calibrated during mode changes. 14 loopback read/write 0 when set, the CS8952T is placed in a loop back mode. any data sent on the transmit data path is returned on the receive data path. loopback mode is entered regardless of whether 10 mb/s or 100 mb/s operation has been configured. this bit will be set upon the assertion of the lpbk pin, and will be automatically cleared upon its deas- sertion. 13 speed selection read/write if auto-negotiation is enabled via the an[1:0] pins, reset to 1; otherwise, reset to 0 when bit 12 is clear, setting this bit configures the CS8952T for 100 mb/s operation. clearing this bit sets the configuration at 10 mb/s. when bit 12 is set, this bit is ignored. 12 auto-neg enable read/write if auto-negotiation is enabled via the an[1:0] pins, reset to 1; otherwise, reset to 0 setting this bit enables the auto-negotiation process. when this bit is set, bits 13 and 8 have no affect on the link configuration. the link configuration is deter- mined by the auto-negotiation process. clearing this bit disables auto-negotiation. 11 power down read/write 0 when this bit is set, the CS8952T enters a low power consumption state. clearing this bit allows normal operation. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 10 isolate read/write if phyad = 00000, reset to 1; other- wise reset to the value on the iso- def pin setting this bit causes the mii data path to be electri- cally isolated by tri-stating all data outputs (i.e. tx_clk, rx_clk, rx_dv, rx_er, rxd[3:0], col, and crs). in addition the CS8952T will not respond to the txd[3:0], tx_en, and tx_er inputs. it will, however, respond to mdio and mdc. clearing this bit allows normal operation.
32 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook basic mode control register - address 00h (cont.) bit name type reset description 9 restart auto-neg read/set 0 setting this bit causes auto-negotiation to be restarted. it is an act-once bit which is cleared once auto-negotiation has begun. clearing this bit has no effect on the auto-negotiation process. 8 duplex mode r/w if auto-negotiation is enabled via the an[1:0] pins, reset to 0; otherwise, reset to 1 when bit 12 is clear, this bit controls the full- duplex/half-duplex operation of the part. when set, the part is configured for full-duplex operation, and when clear the part is configured for half duplex operation. the setting of this bit is superseded by auto-negotiation, and thus has no effect if bit 12 is set. 7 collision test r/w 0 when set, the col pin will be asserted within 10 bit times in response to the assertion of tx_en. upon the deassertion of tx_en, col will be deasserted within 4 bit times. when collision test is clear, col functions normally. 6:0 reserved read only 000 0000
ds206pp3 33 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook basic mode status register - address 01h 15 14 13 12 11 10 9 8 100base-t4 100base-tx/ full duplex 100base-tx/ half duplex 10base-t/ full duplex 10base-t/ half duplex reserved 7 6 5 4 3 2 1 0 reserved mf preamble suppression auto-neg complete remote fault auto-neg ability link status jabber detect extended capability bit name type reset description 15 100base-t4 read only 0 the CS8952T does not support 100base-t4 opera- tion, so this bit will always read 0. 14 100base-tx/full duplex read only 1 when this bit is set, it indicates that the CS8952T is capable of 100base-tx full-duplex operation. this bit reflects the status of the 100base-tx/full-duplex bit in the auto-negotiation advertisement register (address 04h). 13 100base-tx/half duplex read only 1 when this bit is set, it indicates that the CS8952T is capable of 100base-tx half-duplex operation. this bit reflects the status of the 100base-tx/half duplex bit in the auto-negotiation advertisement register (address 04h). 12 10base-t/full duplex read only 1 when this bit is set, it indicates that the CS8952T is capable of 10base-t full-duplex operation. this bit reflects the status of the 10base-t/full duplex bit in the auto-negotiation advertisement register (address 04h). 11 10base-t/half duplex read only 1 when this bit is set, it indicates that the CS8952T is capable of 10base-t half-duplex operation. this bit reflects the status of the 10base-t/half duplex bit in the auto-negotiation advertisement register (address 04h). 10:7 reserved read only 0000 6 mf preamble sup- pression read only 1 when set, this bit indicates that the CS8952T is capa- ble of accepting management frames regardless of whether they are preceded by the preamble pattern. when clear, it indicates that the management frame must be preceded by the preamble pattern to be con- sidered valid. this bit reflects the status of the mr preamble enable bit in the pcs sub-layer configu- ration register (address 17h). 5 auto-neg complete read only 0 this bit is set to a 1 when the auto-negotiation pro- cess has completed. this is an indication that data is valid in the auto-negotiation advertisement register (address 04h), the auto-negotiation link partner ability register (address 05h), and the auto-negotia- tion expansion register (address 06h). 4 remote fault read only 0 when auto-negotiation is enabled, this bit is set if the remote fault bit is set in the auto-negotiation link partner ability register (address 05h). when auto- negotiation is disabled, this bit will be set when a far- end fault indication for 100base-tx is detected.
34 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook basic mode status register - address 01h (cont.) bit name type reset description 3 auto-neg ability read only 1 this bit indicates that the CS8952T has auto-negotia- tion capability. it will always read back a value of 1. 2 link status read only 0 when set, this bit indicates that a valid link has been established. upon a link failure, this bit is cleared and latched. it will remain cleared until this register is read. 1 jabber detect read only 0 in 10base-t mode, if the last transmission is longer than 105 ms, then the packet output is terminated by the jabber logic and this bit is set. if jabberie (inter- rupt mask register (address 10h), bit 3) is set, an mii interrupt will be generated. this bit is implemented with a latching function so that the occurrence of a jabber condition causes it to become set until it is cleared by a read to this register, a read to the interrupt status register (address 11h), or a reset. no jabber detect function has been defined for 100base-tx. 0 extended capability read only 1 this bit indicates that an extended register set may be accessed (registers beyond address 01h). this bit always reads back a value of 1.
ds206pp3 35 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook phy identifier register, part 1 - address 02h 15 14 13 12 11 10 9 8 organizationally unique identifier: bits[3:10] 7 6 5 4 3 2 1 0 organizationally unique identifier: bits[11:18] bit name type reset description 15:0 organizationally unique identifier (bits 3:18) read/write 001ah this identifier is assigned to phy manufacturers by the ieee. its intention is to provide sufficient informa- tion to support 10/100 management as defined in clause 30.1.2 of the ieee 802.3 specification. this register contains bits [3:18] of the oui. bit 3 of the oui is located in bit 15 of the phy identifier, bit 4 of the oui is in bit 14, and so on. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
36 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook phy identifier register, part 2 - address 03h 15 14 13 12 11 10 9 8 organizationally unique identifier - bits[19:24] part number 7 6 5 4 3 2 1 0 part number revision number bit name type reset description 15:10 organizationally unique identifier (bits 19:24) read/write 00 1000 this identifier is assigned to phy manufacturers by the ieee. its intention is to provide sufficient informa- tion to support 10/100 management as defined in clause 30.1.2 of the ieee 802.3 specification. this register contains bits [19:24] of the oui. bit 19 of the oui is located in bit 15 of this register, bit 20 of the oui is in bit 14, and so on. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 9:4 part number read/write 10 0000 these bits indicate the CS8952T part number. it has been set to a value of 100000. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 3:0 revision number read/write revision x these bits indicate the CS8952T part revision. rev. a 0000 rev. b 0001 etc. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
ds206pp3 37 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook auto-negotiation advertisement register - address 04h 15 14 13 12 11 10 9 8 next page acknowledge remote fault technology ability field 7 6 5 4 3 2 1 0 technology ability field protocol selector field bit name type reset description 15 next page read/write 0 when set, this bit enables the ability to exchange next-pages with the link partner. this bit should be cleared if it is not desired to engage in next page exchange. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 14 acknowledge read only 0 when set, this bit indicates consistent reception of the link partners data. 13 remote fault read/write 0 this bit may be used to indicate a fault condition to the link partner. setting this bit will signal to the link partner that a fault condition has occurred. 12:5 technology ability field read/write reset value is dependent on the status of the an[1:0] pins (see ta b l e 5 ) . this field determines the advertised capabilities of the CS8952T as shown below. when the bit is set, the corresponding technology will be advertised dur- ing auto-negotiation. bit capability 12 reserved 11 reserved 10 pause operation for full duplex links. 9 100base-t4 (note: this technology is not sup- ported and can not be set.) 8 100base-tx full duplex 7 100base-tx half duplex 6 10base-t full duplex 5 10base-t half duplex 4:0 protocol selector field read/write 0 0001 this field is used to identify the type of message being sent by auto-negotiation. this field defaults to a value of 00001 for ieee 802.3 messages.
38 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook auto-negotiation link partner ability register - address 05h 15 14 13 12 11 10 9 8 next page acknowledge remote fault technology ability field 7 6 5 4 3 2 1 0 technology ability field protocol selector field bit name type reset description 15 next page read only 0 when set, this bit indicates that the link partner is capable of participating in the next page exchange. 14 acknowledge read only 0 when set, this bit indicates that the link partner has received consistent data from the CS8952T. 13 remote fault read only 0 this bit indicates that a fault condition occurred on the far end. when this bit is set and auto-negotiation is enabled, the remote fault bit in the basic mode status register (address 01h) will also be set. 12:5 technology ability field read only 0000 0000 this field indicates the advertised capabilities of the link partner as shown below. when the bit is set, the corresponding technology has been advertised dur- ing auto-negotiation. bit capability 12 reserved 11 reserved 10 pause operation for full duplex links. 9 100base-t4 8 100base-tx full duplex 7 100base-tx half duplex 6 10base-t full duplex 5 10base-t half duplex 4:0 protocol selector field read only 0 0000 this field is used to identify the type of message being received during auto-negotiation.
ds206pp3 39 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook auto-negotiation expansion register - address 06h 15 14 13 12 11 10 9 8 reserved 7 6 5 4 3 2 1 0 reserved parallel detection fault link partner next page able next page able page received link partner auto-neg able bit name type reset description 15:5 reserved read only 000 0000 0000 4 parallel detection fault read only 0 when set, this bit indicates an error condition in which both the 10base-t and 100base-tx links came up valid, or that one of the technologies estab- lished a link but was unable to maintain the link. this bit is self-clearing. 3 link partner next page able read only 0 when set, this bit indicates that the link partner is capable of next page exchange. 2 next page able read only 1 this bit is a status bit which indicates to the manage- ment layer that the CS8952T supports next page capability. 1 page received read only 0 when set, this bit indicates that a valid word of auto- negotiation data has been received and its integrity verified. the first page of data will consist of the base page, and all successive pages will consist of next page data. this bit is self-clearing. 0 link partner auto- neg able read only 0 when set, this bit indicates that the link partner has auto-negotiation capability.
40 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook auto-negotiation next-page transmit register - address 07h 15 14 13 12 11 10 9 8 next page acknowledge message page acknowledge 2 toggle message/unformatted code field 7 6 5 4 3 2 1 0 message/unformatted code field bit name type reset description 15 next page read/write 0 when set, this bit indicates that more next pages fol- low. when clear, the current page is the last page of data to be sent. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 14 acknowledge read only 0 this bit is used for link code word verification. when set, it indicates that consistent data has been suc- cessfully read from the link partner. 13 message page read/write 1 when set, this bit indicates that the data in the mes- sage/unformatted code field is one of the pre- defined message pages. when low, the data is unfor- matted data. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 12 acknowledge 2 read/write 0 when set, this bit indicates to the link partner that the CS8952T can comply with the last received mes- sage. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 11 toggle read only 0 this bit is used to maintain synchronization with the link partner during next page exchange. 10:0 message/unformat- ted code field read/write 000 0000 0001 this field contains the 11 bit data for the message or unformatted page. it defaults to the null message. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
ds206pp3 41 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt mask register - address 10h this register indicates which events will cause an interrupt event on the mii_irq pin. each bit acts as an enable to the interrupt. thus, when set, the event will cause the mii_irq pin to be asserted. when clear, the event will not affect the mii_irq pin, but the status will still be reported via the interrupt status register (address 11h). 15 14 13 12 11 10 9 8 cim link unstable link status change descrambler lock change premature end error dcr rollover fccr rollover recr rollover remote loopback fault 7 6 5 4 3 2 1 0 reset complete jabber detect auto-neg complete parallel detection fault parallel fail remote fault page received reserved bit name type reset description 15 cim link unstable read/write 0 when set, an interrupt will be generated if an unsta- ble link condition is detected by the carrier integrity monitor function. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 14 link status change read/write 1 when set, an interrupt will be generated each time the CS8952T detects a change in the link status. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 13 descrambler lock change read/write 0 when set, an interrupt will be generated each time the 100base-tx receive descrambler loses or regains synchronization with the far-end. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 12 premature end error read/write 0 when set, an interrupt will be generated when two consecutive idles are detected in a 100base-tx frame without the end-of-stream-delimiter sequence. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
42 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt mask register - address 10h (cont.) bit name type reset description 11 dcr rollover read/write 0 when set, an interrupt will be generated if the msb in the dcr counter becomes set. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 10 fccr rollover read/write 0 when set, an interrupt will be generated if the msb in the fccr counter becomes set. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 9 recr rollover read/write 0 when set, an interrupt will be generated if the msb in the recr counter becomes set. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 8 remote loopback fault read/write 0 when set, an interrupt will be generated if the elastic buffer in the pma is under-run or over-run during remote loopback. this should not occur for normal length 802.3 frames. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 7 reset complete read/write 1 when set, an interrupt will be generated once the dig- ital and analog sections have been reset, and a cali- bration cycle has been performed. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 6 jabber detect read/write 0 when set, an interrupt will be generated when a jab- ber condition is detected by the 10base-t mau. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
ds206pp3 43 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt mask register - address 10h (cont.) bit name type reset description 5 auto-neg complete read/write 0 when set, an interrupt will be generated once auto- negotiation has completed successfully. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 4 parallel detection fault read/write 0 when set, an interrupt will be generated if auto-nego- tiation determines that unstable legacy link signaling was received. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 3 parallel fail read/write 0 when set, an interrupt will be generated when paral- lel detection has occurred for a technology that is not currently advertised by the local device. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 2 remote fault read/write 0 when set, an interrupt will be generated if a remote fault condition is detected either by auto-negotiation or by the far-end fault detect state machine. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 1 page received read/write 0 when set, an interrupt is generated each time a page is received during auto-negotiation. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 0 reserved read only 0
44 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt status register - address 11h this register indicates which event(s) caused an interrupt event on the mii_irq pin. all bits are self-clearing, and will thus be cleared upon readout. 15 14 13 12 11 10 9 8 cim link unstable link status change descrambler lock change premature end error dcr rollover fccr rollover recr rollover remote loopback fault 7 6 5 4 3 2 1 0 reset complete jabber detect auto-neg complete parallel detection fault parallel fail remote fault page received reserved bit name type reset description 15 cim link unstable read only 0 when set, this bit indicates that an unstable link con- dition was detected by the carrier integrity monitor function. 14 link status change read only 0 when set, this bit indicates that a change has occurred to the status of the link. the self status register (address 19h) may be read to determine the current status of the link. 13 descrambler lock change read only 0 when set, this bit indicates that a change has occurred in the status of the descrambler. the self status register (address 19h) may be read to deter- mine the current status of the scrambler lock. 12 premature end error read only 0 this bit is set when a premature end of frame is detected for 100 mb/s operation. a premature end is defined as two consecutive idle patterns detected in a frame prior to the end of stream delimiter. 11 dcr rollover read only 0 this bit is set when the msb of the disconnect count register (address 12h) becomes set. this should provide ample warning to the management layer so that the dcr may be read before rolling over. 10 fccr rollover read only 0 this bit is set when the msb of the false carrier count register (address 13h) becomes set. this should provide ample warning to the management layer so that the fccr may be read before saturat- ing. 9 recr rollover read only 0 this bit is set when the msb of the receive error count register (address 15h) becomes set. this should provide ample warning to the management layer so that the recr may be read before rolling over.
ds206pp3 45 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt status register - address 11h (cont.) bit name type reset description 8 remote loopback fault read only 0 when set, this bit indicates that the elastic buffer has detected an over-run or an under-run condition. in any case, the frame generating this fault will be termi- nated. this should never happen since the depth of the elas- tic buffer (10 bits) is greater than twice the maximum number of bit times the receive and transmit clocks may slip during a maximum length packet assuming clock frequency tolerances of 100 ppm or less. 7 reset complete read only 0 when set, this bit indicates that the internal analog calibration cycle has completed, and all analog and digital circuitry is ready for normal operation. 6 jabber detect read only 0 in 10base-t mode, if the last transmission is longer than 105 ms, then the packet output is terminated by the jabber logic and this bit is set. this bit is implemented with a latching function so that the occurrence of a jabber condition causes it to become set until it is cleared by a read to this register, a read to the basic mode status register (address 01h), or a reset. no jabber detect function has been defined for 100base-tx. this bit is the same as in the basic mode status reg- ister (address 01h). 5 auto-neg complete read only 0 this bit is set when the auto-negotiation process has completed. this is an indication that the auto-negoti- ation advertisement register (address 04h), the auto-negotiation link partner ability register (address 05h), and the auto-negotiation expansion register (address 06h) are valid. this bit is the same as in the basic mode status reg- ister (address 01h). 4 parallel detection fault read only 0 when set, this bit indicates an error condition in which auto-negotiation has detected that unstable 10base-t or 100base-tx link signalling was received. this bit is self-clearing. this bit is the same as in the auto-negotiation expansion register (address 06h) 3 parallel fail read only 0 when set, this bit indicates that a parallel detection has occurred for a technology that is not currently advertised by the local device.
46 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook interrupt status register - address 11h (cont.) bit name type reset description 2 remote fault read only 0 when auto-negotiation is enabled, this bit is set if the remote fault bit is set in the auto-negotiation link partner ability register (address 05h). when auto- negotiation is disabled, this bit will be set when the far-end fault indication for 100base-tx is detected. 1 page received read only 0 when set, this bit indicates that a valid word of auto- negotiation data has been received and its integrity verified. the first page of data will consist of the base page, and all successive pages will consist of next page data. this bit is self-clearing. this bit is the same as in the auto-negotiation expansion register (address 06h). 0 reserved read only 0
ds206pp3 47 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook disconnect count register - address 12h 15 14 13 12 11 10 9 8 disconnect counter 7 6 5 4 3 2 1 0 disconnect counter bit name type reset description 15:0 disconnect counter read/write 0000h this field contains a count of the number of times the CS8952T has lost a link ok condition. this counter is cleared upon readout and will roll-over to 0000h.
48 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook false carrier count register - address 13h 15 14 13 12 11 10 9 8 false carrier counter 7 6 5 4 3 2 1 0 false carrier counter bit name type reset description 15:0 false carrier counter read only 0000h this field contains a count of the number of times the CS8952T has detected a false-carrier -- that is, the reception of a poorly formed start-of-stream delimiter (ssd). the counter is incremented at the end of such events to prevent multiple increments. this counter is cleared upon readout and will saturate at ffffh.
ds206pp3 49 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook scrambler key initialization register - address 14h 15 14 13 12 11 10 9 8 load reserved scrambler initialization key 7 6 5 4 3 2 1 0 scrambler initialization key bit name type reset description 15 load read/set 0 when this bit is set, the scrambler will be loaded with the value in the scrambler initialization key field. when the load is complete, this bit will clear automat- ically. 14:11 reserved read only 0000 these bits should be read as dont cares and, when written, should be written to 0. 10:0 scrambler initializa- tion key read/write reset value is dependent on the phy address field of the self status register (address 19h). this field allows the scrambler to be loaded with a user-definable key sequence. a value of 000h has the effect of bypassing the scrambler function. this is valuable for testing purposes to allow a deter- ministic response to test stimulus without a synchro- nization delay. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
50 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook receive error count register - address 15h 15 14 13 12 11 10 9 8 receive error counter 7 6 5 4 3 2 1 0 receive error counter bit name type reset description 15:0 receive error counter read only 0000h this counter increments for each packet in which one or more receive errors is detected that is not due to a collision event. this counter is cleared upon readout and will roll-over to 0000h.
ds206pp3 51 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook descrambler key initialization register - address 16h 15 14 13 12 11 10 9 8 load reserved descrambler initialization key 7 6 5 4 3 2 1 0 descrambler initialization key bit name type reset description 15 load read/set 0 when this bit is set, the descrambler will be loaded with the value in the descrambler initialization key field. when the load is complete, this bit will clear automatically. 14:11 reserved read only 0000 these bits should be read as dont cares and, when written, should be written to 0. 10:0 descrambler initial- ization key read/write reset value is dependent on the phy address field of the self status register (address 19h). this register allows the descrambler to be loaded with a user-definable key sequence. a value of 000h has the effect of bypassing the descrambler function. this is valuable for testing purposes to allow a deter- ministic response to test stimulus without a synchro- nization delay. note: this field is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
52 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook pcs sub-layer configuration register - address 17h 15 14 13 12 11 10 9 8 reserved time-out select time-out disable repeater mode led5 mode unlock regs mr preamble enable fast test 7 6 5 4 3 2 1 0 clk25 dis- able enable lt/100 cim disable tx disable rx disable led1 mode led4 mode digital reset bit name type reset description 15 reserved read/write 1 this bit is reserved and should be cleared to 0. 14 time-out select read/write 0 when this bit is set, the time-out counter in the receive descrambler is set to time-out after 2 ms with- out idles. when clear the counter is set to time-out after 722 ms without idles. 13 time-out disable read/write 0 when this bit is set, the time-out counter in the receive descrambler is disabled. when this bit is clear, the time-out counter is enabled. 12 repeater mode read/write reset to the value on the repeater pin. this bit defines the mode of the carrier sense (crs) signal. when this bit is set, crs is asserted due to receive activity only. when this bit is clear, crs is asserted due to either transmit or receive activity. 11 led5 mode read/write 0 this bit defines the mode of pin led5 . when this bit is set, pin led5 indicates the synchronization status of the 100base-tx descrambler. when this bit is clear, led5 indicates a collision. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 10 unlock regs read/write 0 when set, this bit unlocks certain read only control registers for factory testing. leave clear for proper operation. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
ds206pp3 53 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook pcs sub-layer configuration register - address 17h (cont.) bit name type reset description 9 mf preamble enable read/write 0 when set, this bit will force all management frames (via mdio, mdc) to be preceded by a 32 bit pream- ble pattern of contiguous ones to be considered valid. when cleared, it allows management frames with or without the preamble pattern. the status of this regis- ter is (inversely) reflected in the mf preamble bit in the basic mode status register (address 01h). note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 8 fast test read/write 0 when set, internal timers are sped up significantly in order to facilitate production test. leave clear for proper operation. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 7 clk25 disable read/write when tcm pin is low, reset to 1; oth- erwise, reset to 0 setting this bit will disable (tri-state) the clk25 output pin, reducing digital noise and power consumption. 6 enable lt/100 read/write 1 when set, normal link status checking is enabled. when clear, this bit forces the link status to link ok (at 100 mb/s), and will assert the link_ok led. 5 cim disable read/write reset to the logic inverse of the value on the repeater pin. when set, this bit forces the carrier integrity monitor function to be disabled. when low, the carrier integ- rity monitor function is enabled, and detection of an unstable link will disable the receive and transmit functions. 4 tx disable read/write 0 when set, this bit forces the 10 mb/s and 100 mb/s outputs to be inactive. when clear, normal transmis- sion is enabled. if tx disable is set while a packet is being transmit- ted, transmission is completed and no subsequent packets are transmitted until tx disable is cleared again. also, if tx disable is cleared while tx_en is high, the transmitter will remain disabled until tx_en is deasserted. this prevents fragments from being transmitted onto the network.
54 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook pcs sub-layer configuration register - address 17h (cont.) bit name type reset description 3 rx disable read/write 0 when set, the receiver is disabled and no incoming packets pass through the receiver. the link will remain established and, if operating at 100 mb/s, the descrambler will remain locked. when clear, the receiver is enabled. if rx disable is set while a packet is being received, reception is completed and no subsequent receive packets are allowed until rx disable is cleared again. also, if rx disable is cleared while a packet is being received, the receiver will remain disabled until the end of the incoming packet. this prevents fragments from being sent to the mac. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 2 led1 mode read/write 0 this bit defines the mode of pin led1 . when this bit is set, pin led1 indicates carrier integrity monitor status as determined by the cim status bit in the self status register (address 19h). when this bit is clear, led1 indicates 10 mb/s or 100 mb/s transmission activity. 1 led4 mode read/write 0 this bit defines the mode of pin led4 . when this bit is set, pin led4 indicates full duplex mode for 10 mb/s or 100 mb/s. when this bit is clear, led4 indicates polarity in 10 mb/s mode or full-duplex in 100 mb/s mode. 0 digital reset read/write 0 when set, this bit will reset all digital logic and regis- ters to their initial values. the analog circuitry will not be affected. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
ds206pp3 55 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook loopback, bypass, and receiver error mask register - address 18h 15 14 13 12 11 10 9 8 bad ssd enable bypass 4b5b reserved bypass symbol alignment endec loopback reserved remote loopback reserved 7 6 5 4 3 2 1 0 strip preamble alternate fdx crs loopback transmit disable code error report select premature end error report select link error report enable packet error report enable code error report enable bit name type reset description 15 bad ssd enable read/write 1 when set, this bit enables the reporting of a bad ssd (false-carrier event) on the mii. these events will be reported by setting rx_er=1, rx_dv=0, and rxd[3:0]=1110. if the 4b5b encoders are being bypassed, this event will be reported by setting rx_dv=0 and rxd[4:0]=11110. if symbol alignment is bypassed, the CS8952T does not detect carrier, and thus will not report bad ssd events. 14 bypass 4b5b read/write reset to the value on the bp4b5b pin. when set, this bit causes the receive 5b4b decoder and the transmit 4b5b encoder to be bypassed. 13 reserved read/write reset to 0. reserved bit, should remain at zero. 12 bypass symbol alignment read/write reset to the value on the bpalign pin. when set, this bit causes the following functions to be bypassed: receiver descrambling, symbol alignment and decoding, transmit symbol encoding, and trans- mit scrambling. 11 endec loopback read/write 0 when set, the 10base-t internal manchester encoder output is connected to the decoder input. when clear, the CS8952T is configured for normal operation. 10 reserved read/write 0 this bit is reserved. 9 remote loopback read/write 0 when set, data received from the link is looped back at the mii and sent back out to the link. received data will be presented on the mii pins. transmit data at the mii will be ignored. note: setting remote loopback and pmd loopback simultaneously will cause neither loopback mode to be entered, and should not be done.
56 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook loopback, bypass, and receiver error mask register - address 18h (cont.) bit name type reset description 8 reserved read/write 0 this bit is reserved. 7 strip preamble read/write 0 when set this bit causes the 7 bytes of mac pream- ble to be stripped off of incoming 100 mb/s frames. the data received across the mii will begin with the 1 byte start of frame delimiter (sfd). note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set. 6 alternate fdx crs read/write 0 this bit changes the behavior of the crs pin only in the full-duplex (fdx) mode of operation. when set, crs will be asserted for transmit data only. when clear, crs will be asserted only for receive data. 5 loopback transmit disable read/write 1 this bit controls whether loopback data is transmitted onto the network. when set, any data transmitted during pmd or endec loopback mode will not be transmitted onto the network. when clear, data will be transmitted on the tx+/- pins as well as looped back onto the mii pins. 4 code error report select read/write 0 when set, this bit causes code errors to be reported by a value of 5h on rxd[3:0] and the assertion of rx_er. when clear, this bit causes code errors to be reported by a value of 6h on rxd[3:0] and the assertion of rx_er. this bit is superseded by the code error report enable bit.
ds206pp3 57 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook loopback, bypass, and receiver error mask register - address 18h (cont.) bit name type reset description 3 premature end error report select read/write 0 when set, this bit causes premature end errors to be reported by a value of 4h on rxd[3:0] and the asser- tion of rx_er. when clear, this bit causes premature end errors to be reported by a value of 6h on rxd[3:0] and the assertion of rx_er. a premature end error is caused by the detection of two idle symbols in the 100 mb/s receive data stream prior to the end of stream delimiter. 2 link error report enable read/write 0 when set, this bit causes link errors to be reported by a value of 3h on rxd[3:0] and the assertion of rx_er. when clear, link errors are not reported across the mii. 1 packet error report enable read/write 0 when set, this bit causes packet errors to be reported by a value of 2h on rxd[3:0] and the assertion of rx_er. when clear, packet errors are not reported across the mii. 0 code error report enable read/write 0 when set, code errors are reported and transmitted on rxd[3:0]. when clear, this bit enables the code error report values on rxd[3:0] as selected by the code error report select bit and also causes the assertion of tx_er to transmit a halt code group. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit of the 10base-t configuration register (address 1ch) is set.
58 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook self status register - address 19h 15 14 13 12 11 10 9 8 link ok power down receiving data descrambler lock disable crs on time-out auto-neg enable status pause fefi enable 7 6 5 4 3 2 1 0 full duplex 10base-t mode cim status phy address bit name type reset description 15 link ok read only 0 when set, this bit indicates that a valid link connec- tion has been detected. the type of link established may be determined from bits 6, 7, and 9. when clear, this bit indicates that a valid link connection does not exist. this bit may be used to determine the current status of the link. 14 power down read only 0 when high, this bit indicates that the CS8952T is in a low power state. 13 receiving data read only 0 this bit is high whenever the CS8952T is receiving valid data. it is a direct copy of the state of the rx_dv pin accessible by software. 12 descrambler lock read only 0 when high, this bit indicates that the descrambler has successfully locked to the scrambler seed of the far- end transmitter and is able to descramble received data. 11 disable crs on time-out read/write reset to the logic inverse of the value on the repeater pin. this bit controls the state of the crs pin upon a descrambler time-out. when set, crs will be forced low upon a descrambler time-out, and will not be released until the descrambler has re-acquired syn- chronization. 10 auto-neg enable status read only if auto-negotiation is enabled via the an[1:0] pins, reset to 1; otherwise, reset to 0. this bit reflects the value of bit 12 in the basic mode control register (address 00h). when set, it indicates that auto-negotiation has been enabled. when clear, this bit indicates that the mode of the CS8952T has been forced to that indicated by bits 6, and 7. 9 pause read only 0 when set, this bit indicates that the flow-control pause function has been negotiated. this indicates that both the local device and the link partner have advertised this capability. 8 fefi enable read/write 0 this bit controls the far-end fault generate and detect state machines. when this bit is set and auto- negotiation is disabled (bit 10 is clear), both state machines are enabled. when clear, this bit disables both state machines. 7 full duplex read only if a full duplex mode is enabled via the an[1:0] pins, reset to 1; otherwise, reset to 0. when set, this bit indicates that the CS8952T has been configured for full-duplex operation. 6 10base-t mode read only 0 when set, this bit indicates that the CS8952T has been configured for 10 mb/s operation.
ds206pp3 59 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook self status register - address 19h (cont.) bit name type reset description 5 cim status read only 0 when clear, this bit indicates that a stable link con- nection has been detected. when an unstable link is detected and the carrier integrity monitor disable bit in the pcs sub-layer configuration register (address 17h) is clear, this bit is set and latched. it will remain set until this register is read. 4:0 phy address field read/write reset to the val- ues on the phyad[4:0] pins. the value on pins phyad[4:0] are latched into this field at power-up or reset. these bits define the phy address used by the management layer to address the phy. the external logic must know this address in order to select this particular CS8952Ts registers individually via the mdio and mdc pins.
60 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook 10base-t status register - address 1bh 15 14 13 12 11 10 9 8 reserved polarity ok 10base-t serial reserved 7 6 5 4 3 2 1 0 reserved bit name type reset description 15:11 reserved read only 0 0000 10 polarity ok read only 0 when high, the polarity of the receive signal (at the rxd+/rxd- inputs) is correct. if clear, the polarity is reversed. if the polarity disable bit of 10base-t con- figuration register (address 1ch) is clear, then the polarity is automatically corrected, if needed. the polarity ok status bit shows the true state of the incoming polarity independent of the polarity disable bit. 9 10base-t serial read/write reset to the value on the 10bt_ser pin. when set, this bit selects 10base-t serial mode. when low, this bit selects 10base-t nibble mode. this bit will only affect the CS8952T if it has been configured for 10 mb/s operation. 8:0 reserved read only 0 0000 0000
ds206pp3 61 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook 10base-t configuration register - address 1ch 15 14 13 12 11 10 9 8 reserved 7 6 5 4 3 2 1 0 national compatibility mode led3 blink enable enable lt/10 sqe enable reserved low rx squelch polarity disable jabber enable bit name type reset description 15:8 reserved read only 0000 0000 7 national compatibil- ity mode read/write 1 when set, registers and bits that are not compatible with the national dp83840 are disabled and writes to these registers are ignored. 6 led3 blink enable read/write 0 when set, led3 will blink during auto-negotiation and will indicate link good status upon completion of auto-negotiation. when clear, led3 indicates link good status only. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit (bit 7) is set. 5 enable lt/10 read/write 1 when set, this bit enables the transmission of link pulses. when clear, link pulses are disabled and a good link condition is forced. if link pulses are disabled during 100 mb/s operation with auto-negotiation enabled, the CS8952T will go into 10 mb/s mode. if operating in 100 mb/s mode with no auto-negotiation, then clearing this bit has no effect. 4 sqe enable read/write reset to the logic inverse of the value on the repeater pin. when set, and if the CS8952T is in half-duplex mode, this bit enables the 10base-t sqe function. when the part is in repeater mode, this bit is cleared and may not be set. 3 reserved read only 1 this bit should be read as a dont care and, when written, should be written to 1. 2 low rx squelch read/write 0 when clear, the 10base-t receiver squelch thresh- olds are set to levels defined by the iso/iec 8802-3 specification. when set, the thresholds are reduced by approximately 6 db. this is useful for operating with quiet cables that are longer than 100 meters. 1 polarity disable read/write 0 the 10base-t receiver automatically determines the polarity of the received signal at the rxd+/rxd- input. when this bit is clear, the polarity is corrected, if necessary. when set, no effort is made to correct the polarity. polarity correction will only be performed dur- ing 10base-t packet reception. note: this bit is disabled, and writes to this bit are ignored when the national compatibility mode bit (bit 7) is set.
62 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook 10base-t configuration register - address 1ch (cont.) bit name type reset description 0 jabber enable read/write 1 when set, the jabber function is enabled. when clear, and if the CS8952T is in 10base-t full-duplex or 10base-t endec loopback mode, the jabber func- tion is disabled. note: when the national compatibility mode bit (bit 7) is set, the jabber function may also be disabled for 10base-t half-duplex, although this is not recom- mended.
ds206pp3 63 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook design considerations the CS8952T is a mixed-signal device containing the high-speed digital and analog circuits required to implement fast ethernet communication. it is important the designer adhere to the following guidelines and recommendations for proper and re- liable operation of the CS8952T. these guidelines will also benefit the design with good emc perfor- mance. twisted pair interface the recommended connection of the twisted-pair interface is shown if figure 6. the unused cable pairs are terminated to increase the common-mode performance. common-mode performance is also improved by connecting the center taps of the rx and tx input circuits to the dc-isolated ground plane. the 0.01 f capacitor c1 must provide 2kv (1,500 vrms for 60 seconds) of isolation to meet 802.3 requirements. if a shielded rj45 connector is used (recommended), the shield should be connect- ed to chassis ground. . internal voltage reference a 4.99 k w 1% biasing resistor must be connected between the CS8952T res pin and ground. this resistor biases the internal analog circuits of the CS8952T and should be placed as close as possible to res pin. connect the other end of this resistor directly to the ground plane. connect the adjacent CS8952T ground pins (pins 85 and 87) to the grounded end of the resistor forming a shield around the res connection. clocking schemes the CS8952T may be clocked using one of three possible schemes: using a 25 mhz crystal and the 49.9 w 0.1f cs8952 tx+ tx- rx+ rx- 80 81 91 92 t1 1 2 3 4 5 6 7 8 rj-45 shld shld 16 15 2 1 14 3 10 11 6 7 12 tg22-3506 5 1% 49.9 w 1% 0.1f 75 w 75 w 0.01f 2kv 51 w 51 w 51 w 51 w 51 w 51 w figure 6. recommended connection of twisted-pair ports (network interface card) 4.99k w vss res vss cs8952 via to ground plane 87 86 85 1% figure 7. biasing resistor connection and layout
64 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook internal oscillator, using an external oscillator sup- plied through the xtal_i pin, or using an external clock source supplied through the tx_clk pin. when a 25 mhz crystal is used, it should be placed within one inch of the xtal_i and xtal_o pins of the CS8952T. the crystal traces should be short, have no vias, and run on the component side. table 10 lists examples of manufacturers of suit- able crystals. the designer should evaluate their crystal selection for suitability in their specific de- sign. alternately, an external cmos clock source may be connected to the xtal_i pin, with xtal_o left open. the input capacitance of the xtal_i pin is larger than the other inputs (a maximum of 35pf), since it includes the additional load capaci- tance of the crystal oscillator. care should be taken to assure any external clock source attached to xtal_i is capable of driving higher capacitive loads. the clock signal should be 25 mhz 0.01% with a duty cycle between 45% and 55%. the third alternative is to supply a ttl-level clock to both a mac and the CS8952Ts tx_clk pin. in this case the xtal_i pin should be left uncon- nected, and the tcm pin should be left unconnect- ed or pulled high. the clock skew between the tx_clk input and the txd[4:0] pins is tightly controlled, assuring data is latched correctly. recommended magnetics the CS8952T requires an isolation transformer with a 1:1 turns ratio for both the transmit and re- ceive signals. table 10 lists examples of manufac- turers with transformers meeting these requirements. however, the designer should evalu- ate the magnetics for suitability in their specific de- sign. power supply and decoupling the CS8952T supports connection to either a 3.3 v or 5.0 v mii. when connected to a +5.0 v mii, all power pins should be provided +5.0 v +/- 5%, and all digital signal inputs should be referenced to +5.0v. when interfaced with a 3.3 v mii, vdd_mii power pins should be provided +3.3 v +/- 5%, vdd power pins should be provided +5.0 v +/- 5%, and all signal inputs, with the ex- ception of xtal_i, should be referenced to +3.3 v. table 10. support component manufacturers each CS8952T power pin should be connected to a 0.1 f bypass capacitor and then to the power plane. the bypass capacitors should be located as close to its corresponding power pin as possible. connect ground pins directly to the ground plane. general layout recommendations the following pcb layout recommendations will help ensure reliable operation of the CS8952T and good emc performance. ? use a multilayer printed circuit board with at least one ground and one power plane. a typi- cal +5v mii application would be as follows: layer 1: (top) components and first choice sig- nal routing layer 2: ground layer 3: power (+5v) component manufacturer part number crystal ecs, inc. international 1105 south ridgeview olathe, ks 66062 usa (913) 782-7787 www.ecsxtal.com ecs-250-18-4-f transformer halo electronics, inc. p.o. box 5826 redwood city, ca 94063 usa (650) 568-5800 www.haloelectronics.com tg22-3506nd bel fuse, inc. 198 van vorst street jersey city, nj 07302 usa (201) 432-0463 www.belfuse.com s5558-5999-46 pulse engineering 12220 world trade drive san diego, ca 92128 usa (619) 674-8100 www.pulseeng.com pe-68515
ds206pp3 65 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook layer 4: (bottom) second choice signal rout- ing, bypass components ? place transformer t1 as close to the rj45 connec- tor as possible with the secondary (network) side facing the rj45 and the primary (chip) side facing the analog side (pins 76-100) of CS8952T. place the CS8952T in turn as close to t1 as pos sible. ? use the bottom layer for signal routing as a sec- ond choice. you may place all components on the top layer. however, bypass capacitors are optimally placed as close to the chip as possible and may be best located underneath the CS8952T on the bottom layer. termination components at the rj-45 and fiber transceiver may also be optimally placed on the bottom layer. ? connect a 0.1 m f bypass capacitor to each CS8952T vdd and vdd_mii pin. place it as close to its corresponding power pin as possible and connect the other lead directly to the ground plane. ? the 4.99k reference resistor should be placed as close to the res pin as possible. connect the other end of this resistor to the ground plane us- ing a via. connect the adjacent vss pins (pins 85 and 87) to the grounded end of the resistor forming a shield as illustrated in figure 7. ? controlled impedance is necessary for critical signals tx+/- and rx+/-. these should be run as microstrip transmission lines (100 w differ- ential, 50 w single-ended). the mii signals should be 68 w microstrip transmission lines. (for short mii signal paths one may standard- ize on a given trace width for all traces without significant degradation in signal integrity.) ? avoid routing traces other than the tx and rx signals under transformer t1 and the rj45 con- nector. signals may run on the bottom side un- derneath the CS8952T as long as they stay away from critical analog traces. ? connect all CS8952T ground and power pins directly to the ground and power planes, re- spectively. note: the vdd_mii power pins may need their own power plane or plane seg- ment in +3.3 v mii applications. ? depending on the orientation and location of the transformer, the CS8952T, and the rj-45, and on whether the application is for a nic or a switch, the rx and tx pairs may need to cross. this should be done by changing layers on a pair by pair basis only, using the minimum number of vias, and making sure that each trace within a pair sees the same path as its peer. figure 6 shows the CS8952T in a nic or adapt- er configuration. it may be configured for a hub or repeater application by changing the wiring to the rj-45 as shown in table 11. ? differential pair transmission lines should be routed close together (one trace width spacing edge-to-edge) and kept at least two trace widths away from other traces, components, etc. tx and rx pairs should be routed away from each other and may use opposite sides of the pcb as necessary, each member of the differential pair should see the same pcb terrain as its peer. ? unused spaces on the signal layers should be filled with ground fill (pour). vias should con- nect the ground patches to the ground plane. this is especially recommended (symmetrical-
66 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook ly) on both sides of the tx+/- traces. table 11. rj-45 wiring ? no signal current carrying planes, i.e. no ground or power plane, should be present un- derneath the region between the transformer secondary (network) side and the rj-45. how- ever, a chassis plane may be added in this re- gion to pick up the metal tabs of a shielded rj- 45. this chassis plane should be separated from the ground and power planes by at least 50 mils. that is, all other ground and power planes should be cookie cuttered so they are voided in the area of the chassis plane. gener- ally speaking, parts should not cross the moat except for the transformer. ? proper termination practices must be used with all transmission lines, especially if sending/re- ceiving high speed signals. series terminations must be kept close to the source and load termi- nations close to the load. ? locate the crystal as close to the CS8952T as possible, running short traces on the compo- nent side in order to reduce parasitic load ca- pacitance. ? add bulk capacitance at each connector where power may be supplied. for example, mii pow- er may be provided at the mii connector and at a separate connector for test purposes. if so, and the two connectors are not adjacent, then the bulk capacitors should be duplicated in each locations. ? use wide traces to connect the unused pairs ter- mination resistors at t1 and the rj-45 to the 2 kv capacitor or capacitors in order to mini- mize their lead inductance. CS8952T pin assignment t1 primary pin assignment t1 secondary pin assignment rj-45 pin assignment adapter/nic configuration hub/repeater configuration 91 (rx+) 1 (rx+) 7 (rx+) 3 (rd+) 1 (rd+) 92 (rx-) 2 (rx-) 6 (rx-) 6 (rd-) 2 (rd-) 81 (tx-) 16 (tx-) 10 (tx-) 2 (td-) 6 (td-) 80 (tx+) 15 (tx+) 11 (tx+) 1 (td+) 3 (td+)
ds206pp3 67 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook specifications and characteristics absolute maximum ratings (avss, dvss = 0 v, all voltages with respect to 0 v.) warning: operation at or beyond these limits may result in permanent damage to the device. normal operation is not guaranteed at these extremes. recommended operating conditions (avss, dvss = 0 v, all voltages with respect to 0 v.) quartz crystal requirements (if a 25 mhz quartz crystal is used, it must meet the following specifications.) parameter symbol min max unit power supply core mii v dd v dd_mii -0.3 -0.3 6.0 6.0 v input current except supply pins - +/-10.0 ma input voltage -0.3 v dd_mii + 0.3 v output voltage -0.3 v dd_mii + 0.3 v ambient temperature power applied -55 +125 c storage temperature -65 +150 c parameter symbol min max unit power supply core mii v dd v dd_mii 4.75 3.0 5.25 5.25 v v operating ambient temperature t a 070c parameter min typ max unit parallel resonant frequency - 25.0 - mhz resonant frequency error (cl = 18 pf) -50 - +50 ppm resonant frequency change over operating temperature -40 - +40 ppm crystal load capacitance - 18 - pf motional crystal capacitance - 0.021 - pf series resistance - - 50 w shunt capacitance - - 7 pf
68 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook dc characteristics (over recommended operating conditions) parameter symbol min typ max unit power supply power supply current 100base-tx (note 1) 10base-t (note 1) 1. with digital outputs connected to cmos loads. i dd - - 135 80 145 - ma hardware power-down (note 1) i ddhpdn -900- a software power-down (note 1) i ddspdn -20-ma low power power-up (note 1) i ddslpup -900-a oscillator xtal_i input low voltage v ixh -0.3 - 0.2 v xtal_i input high voltage v ixh 3.0 - v dd + 0.3 v xtal_i input low current i ixl -40 - - a xtal_i input high current i ixh --40a xtal_i input capacitance c l 35 - pf xtal_i input cycle time t ixc 39.996 - 40.004 ns xtal_i input low time t ixl 18 - 22 ns xtal_i input high time t xh 18 - 22 ns digital i/o output low voltage clk25, mii_irq , spd10, spd100 i ol = 4.0ma led[4:0] i ol = 10.0ma v ol - - - - 0.4 0.4 v output low voltage (mii_drv = 1) col, crs, mdio, rxd[3:0], rx_clk, rx_dv, rx_er, tx_clk i ol = 4.0ma v dd_mii = 5v; i ol = 43.0ma v dd_mii = 3.3v, i ol = 26.0ma v ol - - - - - - 0.4 3.05 2.1 v output low voltage (mii_drv = 0) col, crs, mdio, rxd[3:0], rx_clk, rx_dv, rx_er, tx_clk i ol = 4.0ma v ol -- 0.4 v
ds206pp3 69 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook dc characteristics (cont.) parameter symbol min typ max unit digital i/o (cont.) output high voltage clk25, spd10, spd100 i oh = -4.0ma v oh 2.4 - - v output high voltage (mii_drv = 1) col, crs, mdio, rxd[3:0], rx_clk, rx_dv, rx_er, tx_clk i oh = -4.0ma v dd_mii = 5v; i oh = -20.0ma v dd_mii = 3.3v, i oh = -20.0ma v oh 2.4 1.1 1.1 - - - - - - v output high voltage (mii_drv = 0) col, crs, mdio, rxd[3:0], rx_clk, rx_dv, rx_er, tx_clk i oh = -4.0ma v oh 2.4 - - v input low voltage all inputs except an[1:0], tcm, txslew[1:0], xtal_i v il --0.8v input high voltage all inputs except an[1:0], tcm, txslew[1:0], xtal_i v ih 2.0 - v dd_mii + 0.3 v tri-level input voltages an[1:0], tcm, txslew[1:0] v il v im v ih - 1/3 v dd_mii + 20% 2/3 v dd_mii + 20% - - - 1/3 v dd_mii - 20% 2/3 v dd_mii - 20% - v input low current mdc, txd[3:0], tx_clk, tx_en, tx_er v i = 0.0v mdio v i = 0.0v i il -20 -3800 - - - - m a input high current mdc, txd[3:0], tx_clk, tx_en, tx_er v i = 5.0v mdio v i = 5.0v i ih - - - - 200 20 m a input leakage current all other inputs 0<=v<=v dd i leak -10 - +10 m a
70 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics parameter symbol min typ max unit 10base-t interface transmitter differential output voltage (peak) v od 2.2 - 2.8 v receiver normal squelch level (peak) v isq 300 - 525 mv receiver low squelch level (lorxsquelch bit set) v sql 125 - 290 mv 100base-tx interface transmitter differential output voltage (peak) v op 0.95 - 1.05 v transmitter signal amplitude symmetry v sym 98 - 102 % transmitter differential output impedance z out -100-ohms transmit rise/fall time t rf 3.0 - 5.0 ns transmit rise/fall symmetry t rfs --0.5ns transmit duty cycle distortion t dcd --+/-0.5ns transmit overshoot/undershoot t os --5% transmit jitter t jt - 400 1400 ps receive signal detect assert threshold - - 1.0 v p-p receive signal detect de-assert threshold 0.2 - - v p-p receive signal detect assert time - - 1000 m s receive signal detect de-assert time - - 350 m s
ds206pp3 71 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t serial mode transmit timing tx_clk period t tcp -100-ns tx_clk pulse width t tch , t tcl -50-ns transmit data setup to tx_clk t tds 10 - - ns transmit data hold from tx_clk t tdh 10 - - ns transmit throughput delay t tpd --500ns tx+/- pair jitter into 100 w load t txj --8ns tx+/- pair positive hold time at end of packet t txh 250 - - ns tx+/- pair return to 50 mv after last positive transition t txoff --4.5 s in/out txd0 tx_clk tx+/tx- t tds out tx_en in t txh t tdh t tcp in t txj t tch t tcl t txoff t tpd
72 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t serial mode receive timing allowable received jitter t rxj - - +/-13.5 ns carrier sense assertion delay t rcrsa 300 - 600 ns carrier sense deassertion delay t rcrsd --400ns collision assertion delay t rcola 300 - 600 ns collision deassertion delay t rcold --400ns rx_clk period t rcp -100-ns rx_clk pulse width t rch , t rcl -50-ns carrier sense hold from rx_clk t rcrsh 35 - - ns rx_clk rising edges after carrier sense deas- serted t rcyc 6- -# receive data throughput delay t rlat --250ns receive data setup to rx_clk t rds 35 - - ns receive data hold from rx_clk t rdh 50 - - ns rxd0 rx_clk rx+/rx- t rds t rlat crs t rcp t rch t rcl t rdh t rcrsa t rcrsd col t rcola t rcold t rcyc t rcsrh t rxj
ds206pp3 73 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t jabber/unjabber timing maximum transmit time t jab -105-ms unjabber time t unjab -406-ms parameter symbol min typ max unit 10base-t sqe (heartbeat) timing col (sqe) delay after tx_en off t sqed -1.4- m s col (sqe) pulse width t sqep -1.3- m s t jab tx_en tx+/tx- t unjab col in out out t sqed tx_en tx_clk in/out col t sqep in out t tes
74 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit auto-negotiation and fast link pulses clock/data pulse width t lpw 80 100 130 ns clock pulse to data pulse time t lcdw 55.5 64 69.5 m s clock pulse to clock pulse time t lccw 111 128 139 m s fast link pulse (flp) burst width t flw -2-ms flp burst to flp burst time t lpp 15 16 17 ms fast link pulses per burst 17 - 33 10base-t link integrity first transmitted link pulse after last transmit- ted packet t ln1 15 16 17 ms minimum received link pulses separation t ln4 --7ms maximum received link pulse separation t ln5 50 - - ms last receive activity to link fail (link loss timer) t ln6 50 52 150 ms t lpw fast link pulses flp bursts t lcdw t flw t lpp normal link pulses clock pulse clock pulse data pulse t lccw t lpw
ds206pp3 75 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 100base-x mii receive timing start of stream to crs asserted t rcrsa -1011bt end of stream to crs de-asserted t rcrsd --21bt start of stream to col asserted t rcola --11bt end of stream to col de-asserted t rcold --21bt rx_clk period t rcp -40-ns rx_clk pulse width t rcl, t rch -20-ns "start of stream" to rxd latency aligned alignment bypassed t rlat 12 5 15 - 19 9 bt rxd[3:0],rx_er/rxd4,rx_dv setup to rising edge of rx_clk t rds 10 - - ns rxd[3:0],rx_er/rxd4,rx_dv hold from rising edge of rx_clk t rdh 10 - - ns rx_en asserted to rx_dv, rx_er, rxd[3:0] valid t ren - - 60 ns rx_en de-asserted to rx_dv, rx_er, rxd[3:0], rx_er/rxd4 tristated t rdis - - 60 ns out rxd[4:0], rx_er rx_clk rx+/rx- rx_dv t rds t rlat out out in crs out t rcp t rch t rcl t rdh t rcrsa t rcrsd col out t rcola t rcold rxd[4:0], rx_dv, rx_er rx_en in out t ren t rdis
76 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 100base-x mii transmit timing tx_clk period t tcp -40-ns tx_clk pulse width t tcl, t tch -20-ns txd[3:0], tx_er, tx_en setup to tx_clk high t tds 10 - - ns txd[3:0], tx_er, tx_en hold after tx_clk high t tdh 0- -ns tx_clk to crs asserted latency t tcrsa --8bt tx_clk to crs de-asserted latency t tcrsd --8bt tx_clk to tx+/- output (tx latency) aligned alignment bypassed t tpd 6 - 7 6 8 7 bt in/out txd[4:0], tx_er tx_clk tx+/tx- tx_en t tcrsa in in out crs out t tpd t tcp t tch t tcl t tds t tdh t tcrsd
ds206pp3 77 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t mii receive timing rx+/- preamble to crs asserted t rcrsa -57bt rx+/- end of packet to crs de-asserted t rcrsd 2.5 3 bt rx+/- preamble to col asserted t rcola 0-7bt rx+/- end of packet to col de-asserted t rcold --3bt rx_clk period t rcp -400-ns rx_clk pulse width t rcl, t rch -200-ns "start of stream" to rxd latency t rlat -1317bt rxd[3:0], rx_er, rx_dv setup to rising edge of rx_clk t rds 30 - - ns rxd[3:0], rx_er, rx_dv hold from rising edge of rx_clk t rdh 30 - - ns rx_en asserted to rx_dv, rxd[3:0], rx_er valid t ren - - 60 ns rx_en de-asserted to rx_dv, rxd[3:0]. rx_er in high impedance state t rdis - - 60 ns out rxd[3:0], rx_er rx_clk rx+/rx- rx_dv t rds t rlat out out in crs out t rcp t rch t rcl t rdh t rcrsa t rcrsd col out t rcola t rcold rxd[4:0], rx_dv, rx_er rx_en in out t ren t rdis
78 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t mii transmit timing tx_clk period t tcp -400-ns tx_clk pulse width t tcl, t tch -200-ns txd[3:0], tx_en, tx_er setup to tx_clk high t tds 10 - - ns txd[3:0], tx_en, tx_er hold after tx_clk high t tdh 0- -ns tx_clk to crs asserted latency t tcrsa 0-4bt tx_clk to crs de-asserted latency t tcrsd 0-16bt tx_clk to tx+/- output (tx latency) t tpd 6-14bt tx+/- hold at end of packet t txh 250 - - ns tx+/- return to idle ( <= 50 mv) t txoff --4.5 m s in/out txd[3:0], tx_er tx_clk tx+/tx- tx_en t tcrsa in in out crs out t tpd t tcp t tch t tcl t tds t tdh t tcrsd t txh t txoff
ds206pp3 79 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t serial receive timing allowable receive jitter at bit cell center t rxj --+/- 13.5ns rx+/- active to crs active t rcrsa --600ns crs de-asserted after rx+/- inactive t rcrsd --400ns rx+/- active to col active t rcola --600ns col de-asserted after rx+/- inactive t rcold --400ns rx_clk period t rcp -400-ns rx_clk pulse width t rcl, t rch -200-ns csr hold from rx_clk t rcsrh 5- -ns rx_clk hold after crs off t rcyc 5 - - cycles rxd[0] throughput delay t rlat - - 1200 ns rxd[0] setup from rx_clk t rds 35 - - ns rxd[0] hold from rx_clk t rdh 50 - - ns out rxd0 rx_clk rx+/rx- t rds t rlat in crs out t rcp t rch t rcl t rdh t rcrsa t rcrsd col out t rcola t rcold t rcyc out t rcsrh t rxj
80 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit 10base-t serial transmit timing tx_clk period t tcp -400-ns tx_clk pulse width t tcl, t tch -200-ns txd[0], tx_en setup from tx_clk t tds 10 - - ns txd[0], tx_en hold after tx_clk t tdh 10 - - ns transmit throughput delay t tpd --500ns txd+/- jitter t tpd --+/- 8ns tx+/- hold at end of packet t txh 250 - - ns tx+/- return to idle ( <= 50 mv) t txoff --4.5 m s in/out txd0 tx_clk tx+/tx- t tds out tx_en in t txh t tdh t tcp in t txj t tch t tcl t txoff t tpd
ds206pp3 81 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook switching characteristics (cont.) parameter symbol min typ max unit serial management interface mdc period t mdcp 60 - - ns mdc pulse width t mdcl, t mdch 40 - 60 % mdio setup to mdc (mdio as input) t mdis 10 - - ns mdio hold after mdc (mdio as input) t mdih 10 - - ns mdc to mdio valid (mdio as output) t mdo 0 - 40 ns mdc mdio (input) valid data in in out mdio (output) valid data t mdcp t mdih t mdis t mdo t mdch t mdcl
82 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook mechanical specifications package dimensions dim min max unit a - 1.60 mm a1 0.05 0.15 mm b 0.17 0.27 mm d 15.70 16.30 mm d1 13.90 14.10 mm e 15.70 16.30 mm e1 13.90 14.10 mm e (note 1) 0.40 0.60 mm l 0.45 0.75 mm m 0.00 7.00 degrees 1. nominal pin pitch is 0.50 mm. e1 e d1 d 1 e l b a1 a
ds206pp3 83 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook recommended pcb footprint dim min typ max unit c - 15.40 - mm d - 12.00 - mm e-0.50-mm g 13.80 - 14.00 mm x 0.30 - 0.40 mm y-1.60-mm z 16.80 - 17.00 mm e c d g z y x
84 ds206pp3 CS8952T crystallan? 100base-x and 10base-t transceiver cirrus logic advanced product databook revision history revision changes pp1 - initial publication. pp2 - added electrical and timing specifications. - reformatted register information. - changed order of pin description and electrical specifications sections. pp3 - changed vdd_mii pin description to make it clear it powers all i/o pads except xtal_i, not just mii. - added v ih max specification in dc characteristics section. - changed xtal_i input capacitance specification from max to typ since it is not actually mea- sured at test. - moved electrical specification and pin description sections back where they were in pp1. - added xtal_i pin to v il and v ih exception lists. - fixed pin diagram figure to reverse rx_nrz+/- and test0/1. - added typical pcb footprint in mechanical section. - changed xtal_i electrical specification to reflect the fact it is referenced to vdd instead of vdd_mii. - added more verbiage to functional description.
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