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SM3E ULTRA MINIATURE STRATUM 3E MODULE
2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com
Application
The SM3E Timing Module is a complete system clock module for Stratum 3E timing applications and conforms to GR-1244-CORE (Issue 2), GR-253-CORE (Issue 3) and ITU-T G.812 (Option 3). Applications include shared port adapters, data digital cross connects, ADM's, DSLAM's, multiservice platforms, switches and routers in TDM, SDH and SONET environments. The SM3E Timing Module guarantees full Stratum 3E compliance with a minimum of effort and cost in the smallest complete package available.
Features
Small Package Size, 2.05 x 1.25 x 0.75 inches Eight Auto Select Input References, 8 kHz - 77.76 MHz Phase Buildout Hitless Reference Switching Better than 1ppb initial Hold Over offset Frequency Qualification and Loss of Reference detection for each input Master/Slave Operation with Phase Adjustment Manual/Autonomous Operation Bi-Directional SPI Port Control and Status Reporting Three CMOS Frequency Outputs - Output1 from 1.544 - 77.76MHz, M/ S_Out@8KHz, BITS @2.048 MHz or 1.544 MHz 3.3V operation
Bulletin Page Revision Date Issued By
TM054 1 of 36 02 07 Nov 08 ENG
General Description
The SM3E timing module provides a clock output that meets or exceeds Stratum 3E specifications given in GR-1244-CORE (Issue 2), GR-253-CORE (Issue 3) and ITU-T G.812 (option 3). The SM3E features eight reference inputs. Each input will autodetect the following reference frequencies: 8 kHz, 1.544 MHz, 2.048 MHz, 12.96 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz and 77.76 MHz. The SM3E timing module can be configured during production to produce an output up to 77.76MHz. This output is derived from an onboard VCXO and must be specified when ordering. The second output is a BITS output selectable for either 1.544 or 2.048 MHz. The master/slave output is 8KHz. The user communicates with the SM3E module through a SPI port. The user controls the SM3E operation by writing to the appropriate registers. The user can also enable or disable SPI operation through a SPI_Enable pin. The SM3E offers a wide range of options for the system designer. The bandwidth is SPI Port-selectable from 0.00084 Hz to 1.6 Hz. 0.0016 Hz is the recommended operational bandwidth for Stratum 3E applications. The 8 kHz output has an adjustable pulse width. The pull-in range is also adjustable to establish the desired reference frequency rejection limits. A Free Run frequency calibration value can be written to the module to provide a high degree of accuracy in the free run mode. The reference frequency for any given reference input is automatically detected. A wealth of status information is available through the SPI Port registers. The user also has a choice between autonomous or full manual control operation. In manual mode, the user controls the module operating modes Free Run, Hold Over or locked to a specific reference. If the chosen reference is unavailable or disqualified the module automatically enters Hold Over. In autonomous control mode, operational mode selection occurs automatically based on reference priority and qualification status. When the active reference becomes disqualified, the module will switch to another qualified reference. If none is available, it will switch to Hold Over. In the revertive mode the module will seek to acquire the highest priority qualified reference. In the nonrevertive mode the module will not return to the previous reference even after it is re-qualified unless there are no other qualified references. Switching between references is hitless. Likewise, the output frequency slew rate is minimized during any change of operating mode, including entry into and return from Free Run or Hold Over to protect traffic from transient-induced bit errors. Reference Status information and the operating mode information is accessed through status registers. The module will set the Interrupt pin (SPI_INT) low to indicate a status change. Free Run operation guarantees an output within 4.6ppm of nominal frequency and Hold Over operation guarantees the output frequency will not change by more than 0.012ppm during the first 24 hours. Frequency accuracy is based on a precision oven to provide the stabilty required for Stratum 3E compliance. The SM3E can be programmed to startup in any mode or bandwidth. The module may even be programmed to operate in a fully autonomous mode with no further configuration required. The module operates on 3.3V 5% with a typical power drain of less than 3W at turn on, dropping to approximately 1W @ room temperature after warming up. The module operates over the 0 to 70 C commercial temperature range. Phase buildout can be enabled or disabled by means of the SPI port.
Functional Block Diagram
Figure 1
TRST TCK TDO TDI TMS M/S Input Ref 1 - 8 Reset M/S T1/E1 SPI_ENBL SPI_Clk SPI_In SPI_Out SPI_INT Bus Interface Reference Priority, Revertivity and Mask Table 8 Control Mode Reference Selection Reference Input Monitor OCXO EEPROM DAC VCXO Output 1 M/S Output BITS_Clk
DPLL
APLL LOS LOL Hold_Good
Data Sheet #: TM054
Page 2 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Specifications for Ultra Miniature Stratum 3E
Table 1 Parameter
Voltage Power Reference Frequency 1 - 8 CMOS Output Frequency #1 M/S_Out BITS_Clk Master/Slave I/O Input Reference Pulse Width Free Run Accuracy Hold Over Accuracy Hold Over Stability Dimensions
Specification
3.3V 5% 3W Maximum during start up, 1.5W Typical @ room temperature 8 kHz - 77.76 MHz (Determined by customer's application) 8 kHz - 77.76 MHz 8 kHz 1.544/2.048 MHz (Selectable) 8 kHz 10 ns Min @ 8 kHz, 5 ns Min @ >8 kHz 4.6 ppm 0.001 ppm 0.012 ppm for the first 24 hours 2.05 x 1.25 x 0.75 inches (52.07 x 31.75 x 19.05 mm)
Pin Description
Table 2
Pin # 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 I O I/O O O I I I I I Pin Name LOS LOL M/S REF REF1 REF2 REF3 REF4 TDI TMS TRST BITS_CLK M/S_OUT OUTPUT1 VPP REF5 REF6 REF8 REF7 VPN T1/E1 HOLD_GOOD TDO TCK GND SPI_CLK SPI_IN VCC SPI_ENBL RESET SPI_OUT SPI_INT MASTER SELECT Pin Description Alarm output - Loss of Active Reference Signal Alarm Output - Loss of Lock Master/Slave 8 kHz reference input Reference Input 1 - 8 kHz to 77.76 MHz auto detected Reference Input 2 - 8 kHz to 77.76 MHz auto detected Reference Input 3 - 8 kHz to 77.76 MHz auto detected Reference Input 4 - 8 kHz to 77.76 MHz auto detected JTAG TDI pin JTAG TMS pin JTAG TRST pin 1.544 or 2.048 MHz output selected by pin 14 Master/Slave 8 kHz output Synchronous Primary Output Positive Programming Supply Pin. During normal operation, It is recommended to float this pin. Reference Input 5 - 8 kHz to 77.76 MHz auto detected Reference Input 6 - 8 kHz to 77.76 MHz auto detected Reference Input 8 - 8 kHz to 77.76 MHz auto detected Reference Input 7 - 8 kHz to 77.76 MHz auto detected Negative Programming Supply Pin. During normal operation, It is recommended to float this pin. BITS_CLK select input - 1=1.544 MHz, 0=2.048 MHz Holdover Good Output Flag - 1=Holdover Available JTAG TDO pin JTAG TCK pin Module Ground SPI Port Clock input SPI Port Data input 3.3 Vdc VCC Supply Input SPI Port Enable input - Active Low Module Reset - Active Low SPI Port Data Output SPI Port Interrupt Output Master/Slave select input - 1=Master, 0=Slave
O O O
I I I I O O I
Data Sheet #: TM054
Page 3 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Pin Diagram
Figure 2
SM3E
LOS LOL M/S REF REF1 REF2 REF3 REF4 TDI TMS TRST BITS_CLK M/S_OUT OUTPUT1 VPP REF5 REF6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26
MASTER SELECT SPI_INT SPI_OUT RESET SPI_ENBL Vcc SPI_IN SPI_CLK GND TCK TDO HOLD_GOOD T1/E1 VPN REF7 REF8
(TOP VIEW)
25 24 23 22 21 20 19 18 17
Register Map
Table 3 Address
0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0a 0x0b
Reg Name
Chip_ID_Low Chip_ID_High Chip_Revision Bandwidth_PBO Ctl_Mode Op_Mode Max_Pullin_Range M/S Input_Activity Ref_Activity Ref_Pullin_Sts Ref_Qualified Ref_Mask
Description
Low byte of chip ID High byte of chip ID Chip revision number Bandwidth & Phase Build-Out option Manual or automatic selection of Op_Mode,BITS clock output frequency indication, and frame/multi-frame sync pulse width mode control Master Free Run, Locked, or Hold Over mode, or Slave mode Maximum pull-in range in 0.1 ppm units Cross Reference activity Activities of 8 reference inputs In or out of pull-in range of 8 reference inputs Qualification of 8 reference inputs Availability mask for 8 reference inputs
Type
R R R R/W R/W R/W R/W R R R R R/W
Data Sheet #: TM054
Page 4 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Map Continued
Table 3
0x0c 0x0d 0x0e 0x0f 0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19 0x1a 0x1b 0x1c 0x1d 0x1e 0x1f 0x20 0x21 0x22 0x23 0x24 0x25 0x26 0x27 0x30 0x31 0x32 0x33 0x35 0x37 0x38 0x39 Ref_Available Ref_Rev_Delay Phase_Offset Calibration Fr_Pulse_Width DPLL_Status Intr_Event Intr_Enable Ref1_Frq_Offset Ref2_Frq_Offset Ref3_Frq_Offset Ref4_Frq_Offset Ref5_Frq_Offset Ref6_Frq_Offset Ref7_Frq_Offset Ref8_Frq_Offset Ref1_Frq_Priority Ref2_Frq_Priority Ref3_Frq_Priority Ref4_Frq_Priority Ref5_Frq_Priority Ref6_Frq_Priority Ref7_Frq_Priority Ref8_Frq_Priority FreeRun Priority History_Policy History_CMD HoldOver_Time Cfgdata Cfgctr_Lo Cfgctr_Hi Chksum EE_Wrt_Mode EE_Cmd EE_Page_Num EE_FIFO_Port Availability of 8 reference inputs Reference reversion delay time, 0 - 255 minutes Phase offset between M/S REF & M/S Output (for the Slave in M/S operation) in 250ps resolution Local oscillator digital calibration in 0.05 ppm resolution Frame sync pulse width Digital Phase Locked Loop status Interrupt events Enable individual interrupt events Ref1 frequency offset in 0.2 ppm resolution Ref2 frequency offset in 0.2 ppm resolution Ref3 frequency offset in 0.2 ppm resolution Ref4 frequency offset in 0.2 ppm resolution Ref5 frequency offset in 0.2 ppm resolution Ref6 frequency offset in 0.2 ppm resolution Ref7 frequency offset in 0.2 ppm resolution Ref8 frequency offset in 0.2 ppm resolution Ref1 frequency and priority Ref2 frequency and priority Ref3 frequency and priority Ref4 frequency and priority Ref5 frequency and priority Ref6 frequency and priority Ref7 frequency and priority Ref8 frequency and priority Control and Priority for designation of Free Run as a reference Sets policy for Hold Over history accumulation Save, restore and flush comands for Hold Over history Indicates the time since entering Hold Over state Configuration data write register Configuration data write counter, low byte Configuration data write counter, high byte Configuration data checksum pass/fail indicator Disables/Enables writing to the external EEPROM Read/Write command & ready indication register for ext. EEPROM access Page number for external EEPROM access Read/Write data for external EEPROM access R R/W R/W R/W R/W R R R/W R R R R R R R R R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R R/W R R R R/W R/W R/W R/W
Data Sheet #: TM054
Page 5 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description
The SM3E utilizes up to 8 external references, each from 8 kHz to 77.76 MHz, may be equipped and monitored for signal presence and frequency offset. Additionally, a cross-couple 8 kHz reference input is provided for master/slave operation. Reference selection may be manual or automatic, according to pre-programmed priorities. All reference switches are performed in a hitless manner, and frequency ramp controls ensure smooth output signal transitions. When references are switched, the device provides a controllable phase build-out to minimize phase transitions in the output clocks. Three output signals are provided, the first up to 77.76 MHz , the second fixed at 8 kHz for use as a frame sync signal as well as a cross-couple reference for master/slave operation. In slave mode, the output phase may be adjusted from -32 to +31.75nS relative to the master, to accommodate downstream system needs, such as different clock distribution path lengths. The third output is a BITS clock, selectable as either 1.544 MHz or 2.048 MHz. Device operation may be in Free Run, locked, or Hold Over modes. In Free Run, the clock outputs are simply determined by the Free Run frequency and accuracy of the calibrated internal clock. In locked mode, the chip phase locks to the selected input reference. While locked, a frequency history is accumulated. In Hold Over mode, the chip outputs are generated according to this history. The Digital Phase Locked Loop provides critical filtering and frequency/phase control functions that meet or exceed all requirements in critical jitter and accuracy performance parameters. Filter bandwidth may be configured to suit applications requirements. Control functions are provided via standard SPI bus register interface. Register access provides visibility into a variety of registered information as well as providing extensive programmable control capability. Operating Modes: The SM3E Operates in Either Free Run, Locked, or Hold Over Mode: Free Run - In Free Run mode, Output 1, M/S_Out, and BITS_Clk, the output clocks, are determined directly from and have the accuracy of the calibrated free running internal clock. Reference inputs continue to be monitored for signal presence and frequency offset, but are not used to synchronize the outputs. Locked - The Output 1, M/S_Out, and BITS_Clk, outputs are phase locked to and track the selected input reference. Upon entering the Locked mode, the device begins an acquisition process that includes reference qualification and frequency slew rate limiting, if needed. Once satisfactory lock is achieved, the "Locked" bit is set in the DPLL_Status register, and a compilation of the frequency history of the selected reference is started. When a usable Hold Over history has been established, the Hold_Good pin is set, and the "Hold Over Available" bit is set in the DPLL_Status register. Phase comparison and phase lock loop filtering operations in the SM3E are completely digital. As a result, device and loop behavior are entirely predictable, repeatable, and extremely accurate. Carefully designed and proven algorithms and techniques ensure completely hitless reference switches, operational mode changes, and master/slave switches. Basic loop bandwidth is programmable from 0.84 mHz to 1.6 Hertz, giving the user a wide range of control over the system response. When a new reference is acquired, maximum frequency slew limits ensure smooth frequency changes. Once lock is achieved, (<700 seconds for Stratum 3E), the "Locked" bit is set. If the SM3E is unable to maintain lock, Loss of Lock (LOL) is asserted. All transitions between locked, Hold Over and Free Run modes are performed with minimal phase events and smooth frequency and phase transitions. Reference phase hits or phase differences encountered when switching references (or when entering locked mode) are nulled out with an automatic phase build-out function. Phase build-out is performed with a residual phase error of less than 1 nS, and can optionally be disabled for hits on the selected reference, as required for Stratum 3E. Hold Over - Upon entering Hold Over mode, the Output 1, M/S_Out, and BITS_Clk, outputs are determined from the Hold Over history established for the last selected reference. Output frequency is determined by a weighted average of the Hold Over history, and accuracy is determined by the internal clock. Hold Over mode may be entered manually or automatically. Automatic entry into Hold Over mode occurs when operating in the automatic mode, the reference is lost, and no other valid reference exists. The transfer into and out of Hold Over mode is designed to be smooth and free of transients. The frequency slew is also limited to a maximum of 2 ppm/sec. The history accumulation algorithm uses a first order frequency difference filtering algorithm. Typical holdover accumulation takes about 15 minutes. When a usable holdover history has been established, the Hold_Good pin is set, and the "Holdover Available" bit is set in the DPLL_Status register. The holdover history continues to be updated after "Holdover Avaialble" is declared. The algorithm accumulates the holdover history only when it has locked on either an external reference in Master operation or the M/S Ref clock in Slave operation, starting 15 minutes after power up. Tracking will be suspended automatically when switching to a new reference and in Free Run or Hold Over mode. A set of registers allows the application to control a holdover history maintenance policy, enabling either a re-build or continuance of the history when a reference switch occurs.
Data Sheet #: TM054
Page 6 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description continued
Furthermore, under register access control, a backup holdover history register is provided. It may be loaded from the active holdover history or restored to the active holdover history. The active holdover history may also be flushed. Holdover mode may be entered at any time. If there is no holdover history available, the prior output frequency will be maintained. When in holdover, the application may read (via register access) the time since holdover was enterred. Master/Slave Operation Pairs of SM3E devices may be operated in a master/slave configuration for redundant timing source applications. A typical configuration is shown below.:
Master / Slave Configuration
Figure 3
REFS1-8 M/S REF
SM3E STC3500 1
M/S_OUT / OUTPUT1 / BITS
M/S REF
REFS1-8
SM3E 2
M/S_OUT / OUTPUT1 / BITS
The M/S Output or the Output 1 of each device may be cross-connected to the other device's M/S Ref input. The device auto-detects the frequency on the M/S Ref input. Master or slave state of a device is determined by the M/S pin. Thus, master/slave state is always manually controlled by the application. The master synchronizes to the selected input reference, while the slave synchronizes to the M/S Ref input. (Note that 8kHz frame phase alignment is maintained across a master/slave pair of devices only if M/S Output is used as the cross couple signal.) The unit operating in slave mode locks on and phase-aligns to the cross-reference clock (M/S Output or Output 1) from the unit in master mode. The phase skew between the input cross-reference and the output clock for the slave unit is typically less than 1ns (under 3ns in dynamic situations, including reference jitter and wander). Perfect phase alignment of the two Output 1 output clocks would require no delay on the cross-reference clock connection. To accommodate path length delays, the SM3E provides a programmable phase skew feature. The slave's Output 1 or M/S Output may be phase shifted -32nS to +31.75nS relative to M/S Input according to the contents of the MS_Phase_Offset register to compensate for the path length of the M/S Output or Output 1 to M/S Input connection. This offset may therefore be programmed to exactly compensate for the actual path length delay associated with the particular application's cross-reference traces. The offset may further be adjusted to accommodate any output clock distribution path delay differences. Thus, master/slave switches with the SM3 devices may be accomplished with near-zero phase hits. The first time a unit becomes a slave, such as immediately after power-up, its output clock phase starts out arbitrary, and will quickly phase-align to the cross-reference from the master unit. The phase skew will be eliminated (or converged to the programmed phase offset) step by step. The whole pull-in-and-lock process will complete in about 60 seconds. There is no frequency slew protection in slave mode. In slave mode, the unit's mission is to lock to and follow the master. Once a pair of units has been operating in aligned master/slave mode, and a master/slave switch occurs, the unit that becomes master will maintain its output clock phase and frequency while a phase build-out (to the current output clock phase) is performed on its selected reference input. Therefore, as master mode operation commences, there will be no phase or frequency hits on the clock output. Likewise, the unit that becomes the slave will maintain its output clock frequency and phase for 1 msec before starting to follow the cross-reference, protecting the downstream clock users during the switch. Assuming the phase offset is programmed for the actual propagation delay of this cross-reference path, there will again be no phase hits on the output clock of the unit that has transitioned from master to slave.
Data Sheet #: TM054
Page 7 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description continued
Serial Communication The user can control the operation of the SM3E module through the SPI port. Timing diagrams are shown below. When SPI_ENABLE is high, SPI_OUT is in a Tri-state mode.
Serial Interface Timing, Read Access
Figure 4
SPI_Enable
tCS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SPI_Clk
tRWs tRWh A0
LSB
tCH A2 A3
tCL A4 A5 A6 0
MSB
SPI_In SPI_Out
A1
tDRDY D0
LSB
D1
D2
D3
D4
D5
D6
D7
MSB
Serial Interface Timing, Write Access
Figure 5
SPI_Enable
tCS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SPI_Clk
tCH A2 A3 tCL A4 A5 A6 1
MSB
tRWs
tRWh A0
LSB
SPI_In
A1
D0
LSB
D1
D2
D3
D4
D5
D6
D7
MSB
Data Sheet #: TM054
Page 8 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description continued Serial Interface Timing
Table 4 Symbol
tCS tCH tCL tRWs tRWh tDRDY tHLD tCSTRI tCSMIN
Parameter
SPI_Enable low to SPI_CLK low SPI_CLK high time SPI_CLK low time Read/Write setup time Read/Write hold time Data ready Data Hold Chip Select to data tri-state
Minimum
15 25 25 15 15 15 5
Nominal
-
Maximum
25 -
Units
ns ns ns ns ns ns ns ns ns
Notes
Minimum delay between successive accesses300
Note: The SPI port should not be accessed until 1200ms after reset has transitioned from low to a high state.
Reference Input Quality Monitoring Each reference input is monitored for signal presence and frequency offset. Signal presence for the Ref1-8 inputs is indicated in the Ref_Activity register and signal presence for the M/S REF is indicated in bit 0 of the M/S REF_Activity register. The frequency offset between the Ref1-8 inputs and the calibrated local oscillator is available in the Ref_Frq_Offset registers (8). Register Ref_Pullin_Sts indicates, for each of the Ref1-8 inputs, if the reference is within the maximum pull-in range. The maximum pull-in range is indicated in register Max_Pullin_Range, and may be set in 0.1ppm increments. Typically, it would be set according to the values specified by the standards (GR-1244) appropriate for the particular stratum of operation. The Ref_Qualified register contains the "anded" condition of the Ref_Activity and Ref_Pullin_Sts registers for each of the Ref1-8 inputs, qualified for 10 seconds. When a reference signal has been present for > 10 seconds and is within the pull-in range, it's bit is set. The Ref_Available register contains the "anded" condition of the Ref_Qualified register and the Ref_Mask register, and therefore represents the availability of a reference for selection when automatic reference and operational mode selection is enabled. Reference Input Selection, Frequencies, and Mode Selection One of eight reference input signals (Ref 1-8) are selected for synchronization in Master mode (as below in the Op_Mode register description. 0x05). Ref 1-8 may each be 8 kHz, 1.544 MHz, 2.048 MHz, 12.96 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz or 77.76 MHz. Reference frequencies are auto-detected and the detected frequency can be read from the Ref_Frq_Priority registers (See Register Descriptions and Operation section). Active reference and operational mode selection may be manual or automatic, as determined by bit 1 in the Ctl_Mode register. In manual mode, register writes to Op_Mode select the reference and mode. The reset default is manual mode. The M/S REF input for slave operation is frequency auto-detected and may be 8kHz, 1.544MHz, 2.048MHz, 12.96MHz, 19.44MHz, 25.92MHz, 38.88MHz, 51.84MHz or 77.76MHz. Signal presence and frequency for the M/S REF input is indicated in bits 0-3 of the M/S REF_Activity register. In automatic mode, the reference is selected according to the priorities written to the eight Ref_Frq_Priority registers. Individual references may be masked for use/non-use according to the Ref_Mask register. A reference may only be selected if it is "available" that is, it is qualified, as indicated in the Ref_Qualified register, and is not masked (See Reference Input Quality Monitoring and Register Descriptions and Operation sections). Furthermore, Bit 3 of each Ref_Frq_Priority register will determine if that reference is revertive or non-revertive. When a reference fails, the next highest priority "available" (signal present, non-masked, and acceptable frequency offset) reference will be selected. When a reference returns, it will be switched to only if it is of higher priority and the current active reference is marked "Revertive". Additionally, the reversion is delayed according to the value written to the Ref_Rev_Delay register (From 0 to 255 minutes).
Data Sheet #: TM054
Page 9 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description continued
The automatic reference selection is shown in the following state diagram:
Automatic Reference Selection
Figure 6
Stay Locked on Ref m time for t= Ref_Rev_Delay
Ref_Rev_Delay time expired
Ref n returns, Ref m marked "revertive"
Ref n returns, Ref m marked "non-revertive"
Locked on Ref n
Loss of Ref n
Select new reference: Next highest priority, Qualified (within max. pull-in range, signal present > 10 sec.), Non-masked
Select & Lock on Ref m
The operational mode is according to the following state diagram: No available reference and no Hold Over history Ref loss w/no good Hold Over history and no other available reference
Automatic Operational Mode Selection
Figure 7
Reference Available (Select highest priority) Higher priority Ref return with prior reference marked "revertive" Locked Ref loss w/no good hold over history and no other available reference Ref Return Free Run Ref Return Hold Over Ref Loss w/good hold over history and no alternate reference available Ref Loss w/alternate reference available
No available reference and no hold over history
Data Sheet #: TM054
Page 10 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Detailed Description continued
Output Signals and Frequency Output 1 is the primary chip output, and in locked mode is synchronized to the selected reference. Output 1 may be any of the following frequencies: 12.96 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz or 77.76 MHz. M/S_Out is an 8 kHz output available as a frame reference or synchronization signal for cross-coupled pairs of SM3E devices operated in master/slave mode. In master mode, M/S_Out is synchronized to the selected reference. In slave mode, M/S_Out is in phase with the M/S REF offset by the value written to the Phase_offset register (+31.75 to -32nS, with .25nS resolution). M/S_Out may be a 50% duty cycle signal, or variable high-going pulse width, as determined by the Ctl_Mode and Fr_Pulse_Width registers. In variable pulse width mode, the width may be from 1 to 15 multiples of the Output 1 cycle time. See Register Descriptions and Operation section. BITS_Clk is the BITS clock output at either 1.544 MHz or 2.048 MHz. It is selected by the T1/E1 input and its state may be read in bit 3 of the Ctl_Mode register. When T1/E1 = 1, the BITS frequency is 1.544 MHz, and when T1/E1 = 0, the BITS frequency is 2.048 MHz. Interrupts The SM3E module supports eight different interrupts and appears in INTR_EVENT (0x12) register. Each interrupt can be individually enabled or disabled via the INTR_ENABLE (0x13) register. Each bit enables or disables the corresponding interrupt from asserting the SPI_INT pin. Interrupt events still appear in the INTR_EVENT (0x12) register independent of their enable state. All interrupts are cleared once INTR_EVENT (0x12) register is read. The interrupts are: * Any reference changing from available to not available * Any reference changing from not available to available * M/S REF changing from activity to no activity * M/S REF changing from no activity to activity * DPLL Mode status change * Reference switch in automatic reference selection mode * Loss of Signal * Loss of Lock Interrupts and Reference Change in Autonomous Mode Interrupts can be used to determine the cause of a reference change in autonomous mode. Let us assume that the module is currently locked to REF1. The module switches to REF2 and SPI_INT pin is asserted. The user reads the INTR_EVENT (0x12) register. If the module is operating in autonomous non-revertive mode, the cause can be determined from bits 4, 5, 6 and 7. Bit 5 is set to indicate Active reference change. If Bit 6 is set then the cause of the reference change is Loss of Active Reference. If Bit 7 is set then the cause of the reference change is a Loss of Lock alarm on the active reference. If the module is operating in autonomous revertive mode, the cause can be determined from bits 1, 4,5, 6 and 7. Bit 5 is set to indicate Active reference change. If Bit 6 is set then the cause of the reference change is Loss of Active Reference. If Bit 7 is set then the cause of the reference change is a Loss of Lock alarm on the active reference. If Bit 1 is set then the cause of the reference change is the availability of a higher priority reference. Note: The DPLL Mode Status Change bit (Bit 4) is also set to indicate a change in DPLL_STATUS (0x11) register, during an interrupt caused by a reference change. The data in DPLL_STATUS (0x11) register however is not useful in determining the cause of a reference change. This is because bits 0-2 of this register always reflects the status of the current active reference and hence cannot be used to determine the status of the last active reference. Interrupts in Manual Mode In manual operating mode, when the active reference fails due to a Loss of Signal or Loss of Lock alarm, an interrupt is generated. For example, in case of a Loss of Signal, bits4 and 6 of INTR_EVENT (0x12) register would be set to indicate Loss of Signal and DPLL Mode Status Change. The user may choose to read the DPLL_STATUS (0x11) register, though in manual mode bit6 of INTR_EVENT (0x12) register is a mirror of bit0 of DPLL_STATUS (0x11) register. This holds true for a Loss of Lock alarm, where bit7 of INTR_EVENT (0x12) register is a mirror of bit1 of DPLL_STATUS (0x11) register. Internal Clock Calibration The internal clock may be calibrated by writing a frequency offset v.s. nominal frequency into the Calibration register. This calibration is used by the synchronization software to create a frequency corrected from the actual internal clock output by the value written to the Calibration register. See register descriptions.
Data Sheet #: TM054
Page 11 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation
Chip_ID_low, 0x00 (R)
Bit 7 ~ Bit 0
Low byte of chip ID: 0x11
Chip_ID_High, 0x01 (R)
Bit 7 ~ Bit 0
High byte of chip ID: 0x30
Chip_Revision, 0x02 (R)
Bit 7 ~ Bit 0
Chip revision number: 0x02
Bandwidth_PBO, 0x03 (R/W)
Bit 7 ~ Bit 5
Reserved
Bit 4
Phase Build-out Option: 1: Enable 0: Disable Default: 1
Bit 3 ~ Bit 0
Bandwidth Selection in Hz: 0000: 0.00084 0001: 0.0016 0010: 0.0032 0011: 0.0063 0100: 0.012 0101: 0.025 0110: 0.049 0111: 0.098 (Reset Default) 1000: 0.20 1001: 0.39 1010: 0.78 1011 - 1111: 1.6 BITS 3 - 0 select the phase lock loop bandwidth in Hertz. The reset default is 0.098 Hz. Bit 4 enables or disables phase build-out for active reference phase hits. Phase build-out operation requires register access operation of the device.
Ctl_Mode, 0x04 (R/W)
Bit 7 ~ Bit 6
Reserved
Bit 5
Default: 0
Bit 4
M/S Output Pulse width control: 0: 50% 1: Controlled by FR_Pulse_Width register Default: 0
Bit 3
BITS Clock Output Frequency: 1: 1.544 MHz 0: 2.048 MHz (read only)
Bit 2
HM Ref: 0: Register control of op mode/ref (Will always be 0)
Bit 1
Active Reference Selection: 1: Manual 0: Automatic Default: 1
Bit 0
Reserved
When bit 1 is reset (automatic reference and mode selection), Bits 3 - 0 of the Op_Mode register become read-only. The power-up default for Bit 1 = 1 for manual reference selection and default for Bit 4 = 0 for 50% duty cycle on M/S Output. When the device is in slave mode, it will lock to the M/S REF, independent of the values written to BITS 3 - 0 of the Op_mode register. The operational mode and reference selection written to Bits 3 - 0 while in slave mode will, however, take effect when the device is made the master. When bit 1 of the Ctl_Mode register is reset (automatic reference and mode selection) and the device is in master mode, BITS 3 - 0 of the Op_Mode register become read-only.
Data Sheet #: TM054
Page 12 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
Op_Mode, 0x05 (R/W)
Bit 7 ~ Bit 5
Reserved
Bit 4
Master or Slave Mode 1: Master 0: Slave (Read Only)
Bit 3 ~ Bit 0
Free Run, Locked, or Hold Over: 0000: Free Run mode 0001: Locked on Ref1 0010: Locked on Ref2 0011: Locked on Ref3 0100: Locked on Ref4 0101: Locked on Ref5 0110: Locked on Ref6 0111: Locked on Ref7 1000: Locked on Ref8 1001 - 1111: Hold Over
Max_Pullin_Range, 0x06 (R/W)
Bit 7 ~ Bit 0
Maximum pull-in range in 0.1 ppm unit This register should be set according to the values specified by the standards (GR-1244) appropriate for the particular stratum of operation. The power-up default value is 10 ppm. (= 4.6ppm aging + 4.6 ppm pullin + margin).
M/S REF_Activity, 0x07 (R)
Bit 7 ~ Bit 4
Reserved
Bit 3 ~ Bit 0
Cross reference activity 0000: No signal 0001: 8kHz 0100: 12.96MHz 0101: 19.44MHz 0110: 25.92MHz 0111: 38.88MHz 1000: 51.84MHz 1001: 77.76MHz 1010-1111: Reserved
Indicates signal presence and auto-detected frequency for the M/S REF input.
Ref_Activity, 0x08 (R)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
ref4 activity 1: on 0: off
Bit 2
ref3 activity 1: on 0: off
Bit 1
ref2 activity 1: on 0: off
Bit 0
ref1 activity 1: on 0: off
ref8 activity ref7 activity ref6 activity ref5 activity 1: on 1: on 1: on 1: on 0: off 0: off 0: off 0: off Each bit indicates the presence of a signal for that reference.
Data Sheet #: TM054
Page 13 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
Ref_Pullin_Sts, 0x09 (R)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ref1 sts 1: in range 0: out range
ref8 sts ref7 sts ref6 sts ref5 sts ref4 sts ref3 sts ref2 sts 1: in range 1: in range 1: in range 1: in range 1: in range 1: in range 1: in range 0: out range 0: out range 0: out range 0: out range 0: out range 0: out range 0: out range Each bit indicates if the reference is within the frequency range specified by the value in the Max_Pullin register.
Ref_Qualified, 0x0a (R)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ref8 qual: ref7 qual: ref6 qual: ref5 qual: ref4 qual: ref3 qual: ref2 qual: ref1 qual: 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. This register contains the "anded" condition of the Ref_Activity and Ref_Pullin_Sts registers for each of the Ref1-8 inputs, qualified for 10 seconds. When a reference signal has been present for > 10 seconds and is within the pull-in range, its bit is set.
Ref_Mask, 0x0b (R/W)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ref8 mask: ref7 mask: ref6 mask: ref5 mask: ref4 mask: ref3 mask: ref2 mask: ref1 mask: 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Individual references may be marked as "available" or "not available" for selection in the automatic reference selection mode (bit 1 = 0 in the Ctl_Mode register). The reset default value is 0, "not available". In manual reference selection, either hardware or register controlled, the reference masks have no effect, but do remain valid and are applied upon a transition to automatic mode.
Ref_Available, 0x0c (R)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
ref2 avail: 1: avail. 0: not avail.
Bit 0
ref1 avail: 1: avail. 0: not
ref8 avail: ref7 avail: ref6 avail: ref5 avail: ref4 avail: ref3 avail: 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 1: avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. 0: not avail. This register contains the "anded" condition of the Ref_Qualified and Ref_Mask registers.
Ref_Rev_Delay, 0x0d (R/W)
Bit 7 ~ Bit 0
Reference reversion delay time, 0 - 255 minutes. default = 0000 0101, 5 minutes In automatic reference selection mode, when a reference fails and later returns, it must be available for the time specified in the Ref_Rev_Delay register before it can be switched back to as the active reference (if the new reference was marked as "revertive").
Data Sheet #: TM054
Page 14 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
Phase_Offset, 0x0e (R/W)
Bit 7 ~ Bit 0
The 2's complement value of phase offset between Master Output module and Slave Output module, ranges from -32 nS to +31.75 nS Positive Value: Master Output rising edge leads Slave Output Negative Value: Master Output rising edge lags Slave Output In slave mode, the slave's outputs may be phase shifted -32nS to +31.75nS in .25nS increments, relative to M/S according to the contents of the Phase_Offset register, to compensate for the path length of the M/S to M/S connection. If a phase offset is used, then the two SM3E devices would typically be written to the appropriate phase offset values for the respective path lengths of each Master to Slave connection, to ensure that the same relative output signal phases will persist through master/slave switches.
Calibration, 0x0f (R/W)
Bit 7 ~ Bit 0
2's complement value of local oscillator digital calibration in 0.05 ppm resolution To digitally calibrate the free running clock synthesized from the internal clock, this register is written with a value corresponding to the known frequency offset of the oscillator from the nominal center frequency.
Fr_Pulse_Width, 0x10 (R/W)
Bit 7 ~ Bit4
Reserved
Bit 3 ~ Bit 0
Pulse width for M/S clock output, 1-15 multiples of the Sync_Clk clock period. BITS 4 and 5 of the Ctl_Mode register determine if the M/S 8 kHz output is 50% duty cycle or pulsed (high going) outputs. When they are pulsed, the Fr_Pulse_Width register determines the width. Width is the register value multiple of the Sync_Clk clock period. Valid values are 1 - 15. Reset default is 0001. Writing to 0000 maps to 0001.
DPLL_Status, 0x11 (R)
Bit 7 ~Bit 5
Reserved
Bit 4
Hold Over Build Complete 1: Complete 0: Incomplete
Bit 3
Hold Over Available 1: Avail. 0: Not avail.
Bit 2
Locked 1: Locked 0: Not locked
Bit 1
Loss of Lock 1: Loss of Lock 0: No loss of lock
Bit 0
Loss of Signal 1: No activity on active reference 0: Active reference signal present
Bit 0 indicates the presence of a signal on the selected reference. Bit 1 indicates a loss of lock (LOL). Loss of lock will be asserted if lock is not achieved within the specified time for the stratum level of operation, or lock is lost after being established previously. LOL will not be asserted for automatic reference switches. Bit 2 indicates successful phase lock. It will typically be set in <700 seconds for Stratum 3E with a good reference. It will indicate "not locked" if lock is lost. Bit 3 indicates if a Hold Over history is available. Bit 4 indicates when a new Hold Over history has been sucessfully built and transferred to the active Hold Over history. See Detailed Description section under Interrupts and Reference Change in Autonomous Mode and Interrupts in Manual Mode
Data Sheet #: TM054
Page 15 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
Intr_Event, 0x12 (R)
Bit 7
Loss of Lock
Bit 6
Loss of Signal
Bit 5
Active reference change
Bit 4
DPLL Mode status change
Bit 3
M/S Ref Change from no activity to activity
Bit 2
M/S Ref Change from activity to no activity
Bit 1
Bit 0
Any referAny refererence change erence change from not from available available to able to not available available Interrupt state = 1. When an enabled interrupt occurs, the SPI_INT pin is asserted, active low. All interrupts are cleared and the SPI_INT pin pulled high when the register is read. Reset default is 0. See Detailed Description section under Interrupts and Reference Change in Autonomous Mode and Interrupts in Manual Mode
Intr_Enable, 0x13 (R/W)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Enable Inter- Enable Inter- Enable InterEnable Inter- Enable Inter- Enable InterEnable InterEnable Interrupt event 7: rupt event 6: rupt event 5: rupt event 4: rupt event 3: rupt event 2: rupt event 1: rupt event 0: 1: Enable 1: Enable 1: Enable 1: Enable 1: Enable 1: Enable 1: Enable 1: Enable 0: Disable 0: Disable 0: Disable 0: Disable 0: Disable 0: Disable 0: Disable 0: Disable Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Default: 0 Enables or disables the corresponding interrupts from asserting the SPI_INT pin. Interrupt events still appear in the Intr_Event register independent of their "enable" state. Reset default is interrupts disabled.
Ref(1-8)_Frq_Offset, 0x14 ~ 0x1b (R)
Bit 7 ~ Bit 0
2's complement value of frequency offset between reference and calibrated local oscillator, 0.2ppm resolution These registers indicate the frequency offset, in 0.2ppm resolution, between each reference and the local calibrated oscillator. 0x14 - 0x1b correspond to Ref1 - Ref8.
Ref(1-8)_Frq_Priority, 0x1c ~ 0x23 (R/W)
Bit 7 ~ Bit 4
Bit 3
Bit 2 ~ Bit 0
Frequency Revertivity Priority 0000: None 1: revertive 0: highest 0001: 8 kHz 0: non-revertive 7: lowest 0010: 1.544 MHz Default: 0, Default: 0 0011: 2.048 MHz non revertive 0100: 12.96 MHz 0101: 19.44 MHz 0110: 25.92 MHz 0111: 38.88 MHz 1000: 51.84 MHz 1001: 77.76 MHz 1010-1111: Reserved BITS 2 - 0 indicate the priority of each reference for use in automatic reference selection mode (bit 1 of the Ctl_Mode register =0). In manual reference selection mode (bit 1 of the Ctl_Mode register = 1), these BITS are read-only and will contain either the reset default or values written when last in automatic reference selection mode. For equal priority values, lower reference numbers have higher priority. Bit 3 specifies if the reference is revertive or non-revertive in automatic reference selection mode. When a reference fails, the next highest priority "available" (signal present, non-masked, and acceptable frequency offset) reference will be selected. When a reference returns, it will be switched to only if it is of higher priority and the current active reference is marked "Revertive". BITS 7 - 4 indicate the auto-detected frequency for each reference. Invalid frequencies may result in erroneous device operation. If there is no activity on a reference, bits 7-4will be = 0000. Bits 7-4 are read only. 0x1c - 0x23 correspond to Ref1 - Ref8.
Data Sheet #: TM054
Page 16 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
FreeRun_Priority, 0x24 (R/W)
Bit 7 - Bit 5
Bit 4
Bit 3
Bit 2 - Bit 0
Enable/ Revertivity Priority Disable 1: Enable 0: Highest Reserved 1: Enable 0: Disable 7: Lowest 0: Disable Default: 0 Default: 0 Default: 0 non-revertive Free Run may be treated like a reference. When it is enabled, Free Run will be entered when all references of higher priority are lost or masked. If or when a higher priority reference returns, it is switched to if Free Run is set as "revertive". When disabled, Free Run will be entered only if manually selected or all references fail without an available Hold Over history. For equal priority value, Free Run will be treated as lower priority. History_Policy, 0x25 (R/W)
Bit 7 - Bit 1
Bit 0
Reference Switch Hold Over Hisory Policy Reserved 0: Rebuild 1: Continue Bit 0 determines if Hold Over is retained or rebuilt when a reference switch occurs. See Application Notes, Holdover History Accumulation and Management section.
History_Cmd, 0x26 (R/W)
Bit 7 - Bit 2
Bit 1-0
Hold Over Histroy Commands 01: Save active history to backup history Reserved 10: Restore active history from backup 11: Flush the active history and accumulation register 00: No command Bits 0-1 are written to save a holdover history to the backup history, restore the active holdover history from the backup, or flush the active history. The default value of the register is 00. The last command is latched and may be read by the application. A flush does not affect the backup history. See Application Notes, Holdover History Accumulation and Management section.
HoldOver_Time, 0x27 (R)
Bit 7 - Bit 0
Indicates the time since entering the Hold Over state. from 0-255, one bit per hour. Zero in non-Hold Over state and stops at 255.
Cfgdata, 0x30 (R/W)
Bit 7 - Bit 0
Configuration data write register. Configuration data is written to this register. Internal use only.
Cfgctr_Lo, 0x31 (R)
Bit 7 - Bit 0
Configuration data write counter low byte. Low order byte of configuration data write counter. Internal use only.
Data Sheet #: TM054
Page 17 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Register Descriptions and Operation continued
Cfgctr_Hi, 0x32 (R)
Bit 7 - Bit 0
Configuration data write counter high byte. High order byte of configuration data write counter. Internal use only.
Chksum, 0x33 (R/W)
Bit 7 - Bit 1
Bit 0
Configuration Data Checksum pass/fail indicator 0: Fail 1: Pass
Reserved Checksum verification register for configuration data. Internal use only.
EE_Mode, 0x36 (R/W)
Bit 7 - Bit 1
Reserved EEPROM write enable register.
Bit 0
EEPROM Write Enable 0: Disable 1: Enable
EE_Cmd, 0x37 (R/W)
Bit 7
EEPROM read/write ready bit: 0 = Not Ready 1 = Ready EEPROM read/write command register.
Bit 6 - Bit 2
Bit 1 - Bit 0
EEPROM read/write command bits: 00 = Reset FIFO 01 = Write Command 10 = Read Command
Reserved
EE_Page_Num, 0x38 (R/W)
Bit 7 - Bit 0
EEPROM read/write page number, 0x00 to 0x9f (0 - 159) EEPROM read/write page number register. EEPROM consist of 160 pages.
EE_FIFO_Port, 0x39 (R/W)
Bit 7 - Bit 0
EEPROM read/write FIFO data. EEPROM read/write FIFO port register. EEPROM data is written to/read from this location.
Data Sheet #: TM054
Page 18 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Performance Specifications
Performance Definitions
Jitter and Wander - Jitter and wander are defined respectively as "the short-term and long-term variations of the significant instants of a digital signal from their ideal positions in time". They are therefore the phase or position in time modulations of a digital signal relative to their ideal positions. These phase modulations can in turn be characterized in terms of their amplitude and frequency. Jitter is defined as those phase variations at rates above 10Hz, and wander as those variations at rates below 10Hz. Fractional frequency offset and drift - The fractional frequency offset of a clock is the ratio of the frequency error (from the nominal or desired frequency) to the desired frequency. It is typically expressed as (n parts in 10X), or (n x 10-X). Drift is the measure of a clock's frequency offset over time. It is expressed the same way as offset. Time Interval Error (TIE) - TIE is a measure of wander and is defined as the variation in the time delay of a given signal relative to an ideal signal over a particular time period. It is typically measured in ns. TIE is set to zero at the start of a measurement, and thus represents the phase change since the beginning of the measurement. Maximum Time Interval Error (MTIE) - MTIE is a measurement of wander that finds the peak-to-peak variations in the time delay of a signal for a given window of time, called the observation interval (t). Therefore it is the largest peak-to-peak TIE in any observation interval of length t within the entire measurement window of TIE data. MTIE is therefore a useful measure of phase transients, maximum wander and frequency offsets. MTIE increases monotonically with increasing observation interval. Time Deviation (TDEV) - TDEV is a measurement of wander that characterizes the spectral content of phase noise. TDEV(t is the RMS of filtered TIE, where the bandpass filter is centered on a frequency of 0.42/t.
SM3E Performance
Input Jitter Tolerance - Input jitter tolerance is the amount of jitter at its input a clock can tolerate before generating an indication of improper operation. GR-1244 and ITU-813 requirements specify jitter amplitude v.s. jitter frequency for jitter tolerance. The SM3E device provides jitter tolerance that meets the specified requirements. Input Wander Tolerance - Input wander tolerance is the amount of wander at its input a clock can tolerate before generating an indication of improper operation. GR-1244 and ITU-813 requirements specify input wander TDEV v.s. integration time as shown below.
Integration Time, (seconds)
0.05 < 10 10 < < 1000 1000
TDEV (ns)
100 31.6 x N/A
0.5
The SM3E device provides wander tolerance that meets these requirements. Phase Transient Tolerance - GR-1244 specifies maximum reference input phase transients that a clock system must tolerate without generating an indication of improper operation. The phase transient tolerance is specified in MTIE(nS) v.s. observation time from .001 to 100 seconds, as shown below.
Observation time S (Seconds)
0.001326 S < 0.0164 0.0164 < S < 1.97 1.97 S
MTIE (ns)
61,000 x S 925 + 4600 x S 10,000
The SM3E will tolerate all reference input transients within the GR-1244 specification. Free-run Frequency Accuracy - The ability of a clock to produce a frequency as close as possible to the nominal frequency in the absence of a reference. Hold Over Frequency Stability - A measure of a clock's performance while in Hold Over mode over 24 hours, subjected to the specified temperature variations.
Data Sheet #: TM054
Page 19 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Performance Specifications continued
Wander Generation - Wander generation is the process whereby wander appears at the output of a clock in the absence of input wander. The SM3EG wander generation characteristics, MTIE and TDEV, are shown below, along with the requirements masks (bandwidth = 0.0016 Hz): Wander Generation Characteristics - MTIE
1000
100
GR-253-CORE, Fig 5-17
MTIE (ns)
10 1 0.1 1 10 100 1000 10000 100000
Observation Time (sec)
Wander Generation Characteristics - TDEV
100
10
GR-1244-CORE, R5-4 & GR-253-CORE, Fig 5-18
TDEV (ns)
1
0.1
0.01 0.01 0.1 1 10 100 1000 10000 100000
Integration Time (sec)
Data Sheet #: TM054
Page 20 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Performance Specifications continued
Wander Transfer - Wander transfer is the degree to which input wander is attenuated (or amplified) from input to output of a clock. The GR-1244 requirements for wander transfer limits are shown below.
Integration time, (seconds)
Stratum 3E TDEV (nanoseconds)
N/A N/A 3.16 x
< 0.05 0.05 < 0.1 0.1 < 1.44 1.44 < 10 10 < 300 300 1000 1000 <
10000
-0.5
1.86 x 1.86 x 32.2 x

0.5
N/A
GR-1244-CORE, Fig5-6, Wander Transfer 3E Wander Transfer TDEV
1000
100
TDEV (ns)
10
1
0.1 0.01
0.1
1
10
Integration Time (sec)
100
1000
10000
The SM3E, when configured for the appropriate Stratum 3E bandwidth frequency, meets the Stratum 3E requirements, Jitter Generation - Jitter generation is the process whereby jitter appears at the output of a clock in the absence of input jitter. The device jitter generation performance is as shown below:
Jitter
Broadband (10 Hz - 2 MHz) SONET Band
19.44 MHz
8 ps Typical
77.76 MHz
8 ps Typical
(12 kHz -2MHz) (12 kHz -20MHz) 1.5 ps Typical 0.8 ps Typical Jitter Transfer - Jitter transfer is the degree to which input jitter is attenuated (or amplified) from input to output of a clock. It is a function of the selected bandwidth. The SM3E jitter transfer characteristics are shown below: Jitter Attenuation vs. Input Frequency
Jitter attenuation (dB)
0.0 -10.0 -20.0 -30.0 -40.0 -50.0 -60.0 -70.0 -80.0 0.001
0.01
0.1
1
INPUT Jitter frequency (Hz)
Data Sheet #: TM054
Page 21 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Phase Transients - A phase transient is an unusual step or change in the phase-time of a signal over a relatively short time period. This may be due to switching between equipment, reference switching, diagnostics, entry or exit to/from Hold Over, or input reference transients. The SM3EG performance for reference switches is shown below: Phase Transients - MTIE
10000
GR-253-CORE, Fig 5-19
1000
Requirement
MTIE (ns)
100
Objective
10
1 0.01
0.1
1
10
100
1000
Observation Time (sec)
1us Phase Transients - MTIE
10000
GR-253-CORE, Fig 5-19
1000
MTIE (ns)
100
10
1 0.01
0.1
1
Observation Time (sec)
10
100
1000
Data Sheet #: TM054
Page 22 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Performance Specifications continued
Capture range and Lock range - Capture range and lock range are the maximum frequency errors on the reference input within which the phase locked loop is able to achieve lock and hold lock, respectively. The SM3E Stratum 3E performance is shown below:
Characteristic
Capture range Lock in range
SM3E
15 ppm 15 ppm
Requirement
4.6 ppm N/A
This is the minimum capability, and guarantees the ability to capture and lock with a reference that is offset the maximum allowed in one direction in the presence of an OCXO that is offset the maximum in the opposite direction (4.6 ppm + 4.6 ppm = 9.2 ppm). Master/Slave Skew, Reference switch settling time, and Phase Build-Out resolution - Master/Slave Skew, Reference switch settling time, and Phase Build-Out resolution performance are shown below:
Characteristic
Master/Slave phase skew Reference switch settling time Phase Build-Out resolution
SM3E
< 2 nS Stratum 3E: < 700 sec. up to 20 ppm frequency offset 1 nS
Requirement
N/A Stratum 3E: < 700 sec. up to +/- 4.6 ppm frequency offset < 50 nS
Data Sheet #: TM054
Page 23 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
SM3E Initialization:
Power-up: 1. If possible, always start up in master mode. After the module is powered up, hold the reset pin low for 10ms. Wait 1200ms and read the contents of register 0x33. If it reads1 then the module came up properly. If it reads 0 then reset the module and reread register 0x33 after 1200ms. The contents of 0x33 must read 1 before continuing. 2. Remain in the default free-run mode for 10 seconds then read the value of bit 1 of register 0x11 or pin 2, the LOL alarm output. If the LOL alarm is set, the reset pin must be pulled low as in 1 above. In the free-run mode the LOL alarm should never be set. This indicates the module is in an invalid state. If there is no LOL alarm in free-run the module is ready. Operation: On power up or after a reset all the registers are loaded with their default values. The default values of some important registers are given below assuming the SM34 module operates as a Master Address(Hex) Register Name Value(Binary MSB first) Notes 0x03 Bandwidth_PBO 00000111 Bandwidth = 0.098Hz 0x04 Ctl_Mode 0000r010 r - Read Only 0x05 Op_Mode 00010000 Indicates Free run mode 0x06 Max_Pullin_Range 01100100 0x0b Ref_Mask 00000000 0x0d Ref_Rev_Delay 00000101 0x0e Phase_Offset 00000000 0x0f Calibration 00000000 0x11 DPLL_Status 00000000 Indicates No Active Reference 0x13 Intr_Enable 00000000 Indicates Interrupts are disabled 0x1c-0x23 Ref(1-8)_Frq_Priority xxxx0000 Frequencies are auto detected 0x33 Chksum xxxxxxx1 Bit0 should be high to indicate that data has been loaded correctly from the EEPROM. I. The unit starts up in Free Run and operates in Manual mode. Here are the steps that need to be taken to lock the unit to a reference in Manual mode. 1. Apply signal to the reference inputs. 2. Set the appropriate pull in range by writing to address 0x06. 3. A value of 0001xxxx, depending on which (Ref 1-8) reference to lock to, should be written to address 0x05. 4. Enable Reference mask for appropriate references by writing a 1 to the reference bit in address 0x0b. 5. Enable all Interrupts by writing 11111111 to address 0x13. II. To lock the unit to a reference in autonomous (automatic) mode after power up or reset, the following steps should be taken. You can also switch from Manual to Autonomous mode directly. When doing so, please ensure that the appropriate references are available by checking REF_AVAILABLE register (address: 0x0c). 1. 2. 3. 4. 5. 6. 7. 8. III. Clear bit1 of CTL_MODE register (address: 0x04). This puts the module in autonomous mode. Apply signal to the reference inputs Set the appropriate pull in range by writing to address 0x06 The default bandwidth of 0.098 Hz is appropriate for Stratum 3 operation. Enable Reference mask for appropriate references by writing a 1 to the reference bit in address 0x0b. Set priority and revertivity for the input references by writing to the appropriate Ref_Frq_Priority registers (bits 3-0). Enable all Interrupts by writing 11111111 to address 0x13. Set the unit to operate in autonomous mode by clearing bit1 of address 0x04
Slave Mode Operation: 1. As a Slave, the module operates in Autonomous mode. 2. The Bandwidth is set, by default, to 1.6Hz (Bandwidth_PBO register (Address 0x03): 00001011). 3. Note that bit 4 of the OP_MODE register (Address 0x05) is cleared. 4. The values in Bits 3-0 of this register have no effect on the operation of the Slave module. 5. For the Slave module to track the Master accurately, an appropriate Phase Offset value should be written to PHASE_OFFSET register (Address 0x0e), to compensate for the path delay. 6. The module will lock to the Cross Reference Input (XREF) from the master.
IV RESET Parameters: 1. The reset pin should be held low for a minimum of 10 milliseconds to ensure a complete reset occurs. 2. The SPI interface should not be accessed for a minimum of 1200ms after the reset pin is de-asserted.
Data Sheet #: TM054
Page 24 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes
Available Output1 frequencies are: 12.96 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz or 77.76MHz. After the module is powered up, pull the reset pin low for 10ms. Wait 1200ms and read the contents of register 0x33. If it reads 1 then the module came up properly. If it reads 0 then reset the module and re-read register0c33 after 1200ms. The contents of 0x33 must read 1 before using the module. Reference Inputs - The application may supply up to 8 reference inputs, applied at input pins Ref1 - 8. They may each be 8 kHz, 1.544 MHz, 2.048 MHz, 12.96 MHz, 19.44 MHz, 25.92 MHz, 38.88 MHz, 51.84 MHz or 77.76 MHz. The device auto-detects the reference frequencies, and they may be read from the Ref(1-8)_Frq_Priority registers in register control mode, as described in the control mode sections that follow. Reference switches are performed in a hitless manner. However, if the application externally changes the frequency of a particular reference, the device requires 20ms to auto-detect the new frequency. Manual switches to a frequency changed reference should not be made during this interval. Automatic reference selection mode accounts for the auto-detection in the reference qualification. References would typically (but need not be) connected in decreasing order of usage priority. For example if redundant BITS clocks are available, they would typically be assigned to Ref1 and Ref2, with other transmission derived signals following thereafter. Master/Slave operation - For some applications, reliability requirements may demand that the clock system be duplicated. The SM3E device will support the master/slave duplicated configuration for such applications. To facilitate it's use, the device includes the necessary signal cross coupling and control functions. Redundancy for reliability implies two major considerations: 1) Maintaining separate failure groups such that a failure in one group does not affect it's mate, and 2) Physical and logical partitioning for repair, such that a failed component can be replaced while the mate remains in service, if so desired. System design needs to account to meet system level goals.
Master / Slave Configuration
Figure 8
Reference 1 In
Ref1
SM3E 1
BITS_Clk Output 1 BITS c lock output Synchronized clock output 8 kHz
Reference 8 In
Ref8 STC3500
M/S Output M/S (8KHz)
M/S (8KHz)
Sync_8K Output 1 BITS_Clk
8 kHz Synchronized clock output BITS clock output
Ref1
Ref8
SM3E 2
Data Sheet #: TM054
Page 25 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes continued
Master/Slave Configuration - A pair of devices are interconnected by cross-coupling their respective M/S Outputs or Output1 to the other device's M/S REF input (See Figure 8). Additionally, the reference inputs for each device would typically be correspondingly the same, so that when a Master/Slave switch occurs, synchronization would continue with the same reference. The references may be driven by the same signal directly or via separate drivers, as the redundancy of that part of the system requires. Distribution path lengths are not critical here, as a phase build-out will occur when a device switches from slave to master. The path lengths of the two M/S Output to M/S REF signals is of interest, however. They need not be the same. However, to accommodate path length delays, the SM3E provides a programmable phase skew feature, which allows the application to offset the output clock from the cross-reference signal by -32ns to +31.75ns. This offset may therefore be programmed to exactly compensate for the actual path length delay associated with the particular application's cross-reference traces. The offset may be further adjusted to accommodate any output clock distribution path delay differences. Phase offset is programmed by writing to the Phase_Offset register, and is typically a one-time device initialization function. (See register description and Register Access Control sections). Thus, master/ slave switches with the SM3E devices may be accomplished with near-zero phase hits. For applications that use Hardware Control only (i.e. phase offset programming is not available), it is desirable to keep the cross couple path lengths at a minimum and relatively equal in length, as the path length will appear as a phase hit in the slave clock output when a master/slave switch occurs in a Hardware Control configuration. Master/Slave Operation and Control - The Master/Slave state is always manually controlled by the application. Master or slave state of a device is determined by the MASTER SELECT pin. Choosing the master/slave states is a function of the application, based on the configuration of the rest of the system and potential detected fault conditions. Master/slave switches should be performed with minimal delay between switching the states of each of the two devices. This can be easily accomplished, for example, by controlling the master/slave state with a single signal, coupled to one of the devices through an inverter. While performing Master/Slave switches, one has to make sure that both modules are not in slave mode. This creates a "Timing Loop" that can cause undesirable effects. In the case of Register Access Automatic Control mode, where reference selection is automatic, it is necessary to read the operational mode BITS 3-0) from the master's Op_Mode register and write it to the slave's Op_Mode register. The master's reference selection will then be used by the slave when it becomes master. In addition to having the references populated the same, and in the same order for both devices, it is desireable to write the reference frequency and priority registers Ref(1-8)_Frq_Priority and the Ref_Mask registers to the same values for both devices to ensure seamless master/slave switches. Reset - Device reset is an initialization time function, which resets internal logic and register values. A reset is performed automatically when the device is powered up. Registers return to their default values, as noted in the register descriptions. Device mode and functionality following a reset are determined by the state of the various hardware control pins. Holdover History Accumulation and Maintenance -- Holdover history accumulation and maintenance may be controlled in greater detail if register bus access to the device is provided. Holdover history accumulation and control encompasses three device internal registers, three bus access registers for control and access, and two status bits in the DPLL_Status register.
Hold Over History Accumulation Register
Active Hold Over History
Backup Hold Over History
Once lock has been achieved, holdover history is compiled in the accumulation register. It is transferred to the Active holdover history when it is ready (typically in about 15 minutes). The "Holdover Available" bit and output pin are set to "1". From then on, the Active holdover history is continually updated and kept in sync with the holdover history accumulation register. (See Figure 11).
Data Sheet #: TM054
Page 26 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes continued Hold Over History access and Control Registers
Table 5 Register
0x25 0x26 0x27 0x11
Register Name
History_Policy History_Cmd Holdover_Time DPLL_Status
Description
Sets policy for Hold Over history accumulation: "Rebuild" or "Continue" Save, restore, and flush commands for Hold Over history Indicates the time since entering the Hold Over state Bits 3 and 4: Hold Over Available" and "Hold Over Build Complete"
Hold Over History and Status States
Figure 9
Reference Switch Acquire Reference Hold Control = 0 Hold Available = 0 Reference Lock Reference Switch
Flush
Flush
Build History Hold Control = 0 Hold Available = 0 Flush
History Build Complete
Locked, History Complete Hold Control =1 Hold Available = 1 Reference Lock (with "Continue" set)
Reference Switch History Build Complete, Replace Active Hold Over History
Reference Switch
Acquire Reference Hold Control = 0 Hold Available = 1 Reference Lock (with "Rebuild" set)
Reference Switch Build History Hold Control = 0 Hold Available = 1
History Restored from backup, re-start the building procedure.
Data Sheet #: TM054
Page 27 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes continued
Holdover History Accumulation and Maintenance continued - Whenever holdover is entered, it is the Active Holdover History that is used to determine the holdover frequency. The History_Cmd register allows the application to issue three holdover history control commands: 1) Save the Active Holdover History to the Backup History. 2) Restore a Backup History to the Active. 3) Flush the active History as well as the accumulation register. The Backup history remains intact. Both the Active and the Backup holdover histories are loaded with the calibrated freerun synthesizer control data on reset/power-up. The application might use the "save to backup" in a situation where, for example, the primary reference is known to be of higher quality than any secondary references, in which case it may be desirable to save and then restore the holdover history accumulated on the primary reference if the primary reference is lost and holdover is entered upon loss of a secondary reference. Users can restore the history from backup any time, even while operating in Holdover mode. The frequency transient will be smooth and continuous. It is the responsibility of application software to keep track of the age and viability of the holdover backup history. Given time and temperature effects on oscillator aging, the application may wish to periodically perform a "Save" of the Active history to keep the backup current. When switching to a new reference, the active holdover history will remain intact and marked as "Holdover Available" (if it was available before the reference switch) until a new history is accumulated on the new reference (Typically 15 minutes after lock has been achieved). During the new history accumulation, the "Holdover Build Complete" bit is reset. Once the new history accumulation is complete, it is transferred to the Active History and the "Holdover Build Complete" bit is set. The active history will then continue to be updated to track the reference. The History_Policy register allows the application to control how a new history is built. When set to "Rebuild": 1) History accumulation begins when lock is achieved on the new reference. 2) The holdover history is rebuilt (taking about 15 minutes). The Active History remains untouched until it is replaced when the build is complete. When the policy is set to "Continue": 1) If there is no "Available" Active History, a new build occurs, as under the "Rebuild" policy. 2) If there is an "Available" Active History, it will continue, the accumulation register will be loaded from the Active History, and the "Build" process is essentially completed immediately following lock on the new reference. The "Continue" policy may be used by the application if, for example, it is known that the reference switched to may be traced to the same source and therefore likely has no frequency offset from the prior reference. In that case, the "Continue" policy avoids the delay of rebuilding the holdover history. If the switch is likely to be between references with known or unknown frequency offset, then it is preferable to use the "Rebuild" policy. The time since the holdover state was entered may be read from the Holdover_Time register. Values are from 0 to 255 hours, limited at 255, and reset to 0 when not in the holdover state. Boundary Scan IEEE1149.1-2001 (Limited Testability Support) - This module exposes a boundary scan chain which contains one or more boundary scan testable IEEE1149.1-2001 complaint devices. The exposed boundary scan chain is IEEE1149.1-2001 compliant, and supports all documented testing modes of devices contained within chain. Integration of this module into an existing boundary scan chain will require the following. - Substitution of modules footprint with provided testability model schematic. - Modified net list will need to be loaded into boundary scan test vector generation software. Testability Model Schematic and BSDL file(s) can be obtained directly from factory. Control Modes The device must be operated in a manual control mode, or automatic control and reference selection mode. Reset may be pulled low for a minimum of 10mS during chip start-up (or any other desired time) to initialize the full device state. The BITS clock output frequency is selected by the T1/E1 pin. When T1/E1 = 1, the BITS frequency is 1.544 MHz, and when T1/E1 = 0, the BITS frequency is 2.048 MHz. MASTER SELECT- Determines the master or slave mode. Set to "1" for a master, and "0" for a slave. Master/slave switches should be performed with minimal delay between switching the states of each of the two devices. This can be easily accomplished, for example, by controlling the master/slave state with a single signal, coupled to one of the devices through an inverter. For simplex operation, the device should be in Master mode - set MASTER SELECT to "1".
Data Sheet #: TM054
Page 28 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes continued Phase Build-out Operation
General: The module, when locked to a reference maintains a fixed phase relationship between its input and output signals. The phase detector used in the PLL determines this relationship. Typically, the PLL would recognize a phase change in the input reference and adjust the oscillator control to maintain the same input output relationship. The PLL can be programmed to ignore the input phase change and thereby create a new phase relationship between the input and the output signals. This is particularly useful in some applications where it is not desirable to pass phase hits on the inputs through to the outputs. This process of limiting or absorbing a phase hit is known as "Phase Build Out". Requirements: A module that supports phase build-out should meet the following requirements specified in GR-1244, section 5-7. R5-15 " Input phase-time changes of 3.5us or greater over an interval of less than 0.1seconds or less shall be built-out by stratum 2 and 3E clocks to reduce the resulting clock phase-time change to less than 50ns. Phase-time changes of 1.0us or less over an interval of 0.1seconds shall not be built-out." R5-16 " Stratum 3, 4E and 4 clocks shall not perform phase build-out." "Based on the above requirement, phase-time changes of more than 1.0us but less than 3.5us that occur over an interval of less than 0.1seconds may or may not be built-out". The module should not show any alarms during the phase build-out operation. Also the module should be capable of tolerating 5 to 10 UI of jitter at DS1 rate (3.2 to 6.4 us) and not perform any phase build-out. Module Setup: The module, by default, does not have phase build-out enabled. It can be enabled by setting the "PHASE BUILD-OUT OPTION" bit, which is bit4 of BANDWIDTH_PBO register (0x03).
Note: Phase build-out is not the same as "Hitless Reference Switching" even though they are similar in implementation. While phase build-out is implemented in stratum 3E timing modules and higher, hitless reference switching can be implemented in any stratum level timing module that accepts two or more reference inputs. Also, phase build-out can be used only to build-out phase hits that exceed 1 us, hitless reference switching has no such limits.
Data Sheet #: TM054
Page 29 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Application Notes continued SM3E Application Note on Interrupts
The SM3/3E module supports eight different interrupts and appears in INTR_EVENT (0x12) register. Each interrupt can be individually enabled or disabled via the INTR_ENABLE (0x13) register. Each bit enables or disables the corresponding interrupt from asserting the SPI_INT pin. Interrupt events still appear in the INTR_EVENT (0x12) register independent of their enable state. All interrupts are cleared once INTR_EVENT (0x12) register is read. The interrupts are 1. 2. 3. 4. 5. 6. 7. 8. Any reference changing from available to not available Any reference changing from not available to available M/SREF changing from activity to no activity M/SREF changing from no activity to activity DPLL Mode status change Active reference change Loss of Signal Loss of Lock
Interrupts and Reference change in Autonomous mode: Interrupts can be used to determine the cause of a reference change in autonomous mode. Let us assume that the module is currently locked to REF1. The module switches to REF2 and SPI_INT pin is asserted. The user reads the INTR_EVENT (0x12) register. If the module is operating in autonomous non-revertive mode, the cause can be determined from bits4, 5, 6 and 7. Bit 5 is set to indicate Active reference change. If Bit 6 is set then the cause of the reference change is Loss of Active Reference. If Bit 7 is set then the cause of the reference change is a Loss of Lock alarm on the active reference. If the module is operating in autonomous revertive mode, the cause can be determined from bits 1, 4, 5, 6 and 7. Bit 5 is set to indicate Active reference change. If Bit6 is set then the cause of the reference change is Loss of Active Reference. If Bit 7 is set then the cause of the reference change is a Loss of Lock alarm on the active reference. If Bit 1 is set then the cause of the reference change is the availability of a higher priority reference. Note: The DPLL Mode Status Change bit (Bit 4) is also set to indicate a change in DPLL_STATUS (0x11) register, during an interrupt caused by a reference change. The data in DPLL_STATUS (0x11) register however is not useful in determining the cause of a reference change. This is because bits0-2 of this register always reflects the status of the current active reference and hence cannot be used to determine the status of the last active reference. Interrupts in Manual Mode: In manual operating mode, when the active reference fails due to a Loss of Signal or Loss of Lock alarm, an interrupt is generated. For example, in case of a Loss of Signal, bits 4 and 6 of INTR_EVENT (0x12) register would be set to indicate Loss of Signal and DPLL Mode Status Change. The user may choose to read the DPLL_STATUS (0x11) register, though in manual mode bit6 of INTR_EVENT (0x12) register is a mirror of bit 0 of DPLL_STATUS (0x11) register. This holds true for a Loss of Lock alarm, where bit 7 of INTR_EVENT (0x12) register is a mirror of bit 1 of DPLL_STATUS (0x11) register.
Data Sheet #: TM054
Page 30 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Mechanical Specifications Mechanical Dimensions
Figure 10
2.050 [52.07mm] MAX. .075 [1.91mm]
1.250 [31.75mm] MAX.
1.100 [27.93mm]
.125 [3.17mm] .750 [19.05mm] MAX.
.070 [1.78mm] PIN 1
.018 [.46mm]
.100 [2.54mm]
Footprint Dimensions
Figure 11
TOP VIEW
1.300 1.200
CUSTOMER COMPONENT KEEP OUT AREA
PIN 1
HOLE/PAD SIZE (32 PLACES): 1. 0.034" DIA. PLATED HOLE WITH 0.070" DIA. PAD.
0.100 0.000
1.000
1.100
1.200
1.300
1.400
1.500
1.600
1.700
1.800
0.000
0.300
0.400
0.500
0.600
0.700
0.800
0.900
Data Sheet #: TM054
Page 31 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
2.100
Mechanical Specifications continued Required External Components
1. 2. 3. 4. 5. Place series resistors (33 ohms) on all reference inputs (Pins 4 - 7 & 15-18). Place series resistors (33 ohms) on SPI_IN and SPI_CLK inputs (Pins 25, 26). Place one .01uF and one 47-100uF capacitor at the input power pin (Pin 27). One 4.7uF (25V) capacitor is required at the VPP pin (Pin 14). One 4.7uF (25V) capacitor is required at the VPN pin (Pin 19).
PCB Layout Recommendations
1. 2. 3. 4. 5. 6. Orient module so airflow is parallel along the header strips (pins). Place de-coupling and/or filter components as close to module pins as possible. Do not place any components directly beneath the module on the topside of the host PCB. Ensure that only clean and well-regulated power is supplied to the module. Isolate power and ground inputs to the module from noisy sources. Provide power and ground connections through a 0.050" wide trace (minimum) using 1-oz. Cu or equivalent copper feature (i.e. internal plane, copper area fill, etc.). 7. Keep module signals away from sensitive or noisy analog and digital circuitry. 8. Avoid split ground planes as high-frequency return currents may be affected. 9. Allow extra spacing between traces of high-frequency inputs and outputs. 10.Keep all traces as short as possible - avoid meandering trace paths. 11.Avoid routing signals directly beneath the module on the topside of the host PCB. 12.If possible, provide a copper area directly beneath the module on the topside of the host PCB. Connect this copper area to ground. 13.It is recommended that the connections of the JTAG, VPP and VPN pins be routed to pads, preferably in a SIL pattern as shown in Figure 12 below. It is recommended to use 0.1" center to center spacing.
GND
TDO
TMS
1
Figure 12
Optional Socket Mounting Recommendations
Mating sockets may be used if permanent installation of the SM3 module is not desired. Two possible sources for these sockets include: 1. Samtec, "Low Profile Socket Strips", SL Series, PN SL-116-G-19. (http://www.samtec.com/) 2. Mill-Max, "Single-In-Line Sockets", 315 Series, PN 315-xx-116-41-001. (http://www.mill-max.com/) The SM3E requires two 16-pin sockets. The optional dual footprint configuration shown in Figure 13 requires one 14-pin and two 16-pin sockets.
Data Sheet #: TM054
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
RCK
8
Page 32 of 36 Rev: 02 Date: 11/07/08
TCK
VPN
VPP
TDI
Mechanical Specifications continued Optional SM3/SM3E Dual Footprint
A dual footprint configuration may be used when designing a host circuit board containing the Connor Winfield SM3 or SM3E modules. The smaller SM3 contains a subset of the signal pins found on the larger SM3E in locations which allow for a simple dual footprint arrangement like the one shown in Figure 13.
SM3E
32
LOS LOL M/S REF REF1 REF2 REF3 REF4 TDI TMS TRST BITS_CLK M/S_OUT OUTPUT1 VPP REF5 REF6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
SM3
28 31 27 30 26 29 25 28 24 27 23 26 22
MASTER SELECT SPI_INT SPI_OUT RESET SPI_ENBL Vcc SPI_IN
25
(TOP VIEW)
21 24 20 23 19 22 18 21 17 20 16 19 15 18 17
SPI_CLK GND TCK TDO HOLD_GOOD T1/E1 VPN REF7 REF8
16
0.850" 1.100"
Figure 13
The modules shown in Figure 13 are arranged in a left-justified fashion. Notice that right justified or center justified (with an additional column of SM3 pins) arrangements are also possible, depending on the designer's preference. Placement of external components 1. Place series resistors (33 ohms) at the source of all reference input (SM3 Pins 4 - 7, SM3E Pins 4-7 & 15-18). 2. Place series resistors (33 ohms) at the source of SPI_IN and SPI_CLK inputs (SM3 Pins 21,22, SM3E Pins 25 & 26). 3. Place one .01uF and one 47-100uF capacitor at the input power pin (SM3 Pin 23, SM3E Pin 27). 4. One 4.7uF (25V) capacitor is required at the VPP pin (SM3 & SM3E Pin 14). 5. One 4.7uF (25V) capacitor is required at the VPN pin (SM3 Pin 15, SM3E Pin 19). Be sure to consult Connor Winfield's respective datasheets for additional mechanical, electrical, footprint and keep-out information.
Data Sheet #: TM054
Page 33 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
SM3E Reference Design
Figure 14
LOS LOL M/S INPUT R1 RE F1 RE F2 RE F3 RE F4 R2 R3 R4 R5 33 33 33 33 33 TDI TMS TRST BITS_CLK M/S_OUT OUTPUT1 VPP RE F5 RE F6 R9 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 LOS LOL XREF REF1 REF2 REF3 REF4 TDI TMS TRST BITS_CLK M/S_OUT OUTPUT1 VPP REF5 REF6 SM3E_MODULE L1 BRDVCC_3.3 THFB1608K-301T10 M/S SPI_INT SPI_OUT RESET SPI_ENBL 3.3V SPI_IN SPI_CLK GND TCK TDO HOLD_RDY BITS_SEL VPN REF7 REF8 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 GND TCK TDO HOLD_GOOD T1/E1 VPN R12 33 R11 33 RE F8 RE F7 M/S SPI_INT SPI_OUT RESET SPI_ENBL VCC R14 33 R13 33 SPI_IN SPI_CLK
R10 33
VCC
C1 10uF
C2 0.01uF
NOTES: 1. It is recommended that the incoming References be terminated at source by 33ohm resistors.
Data Sheet #: TM054
Page 34 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Optional Programing Header Reference Design
Figure 15
J2 1 3 5 7 9 11 13 15 17 19 21 23 25 NC NC NC GND GND GND NC NC GND GND NC NC NC VDDP VDDP VPP VPN GND TCK TDI TDO TMS RCK TRST VDD VDD 2 4 6 8 10 12 14 16 18 20 22 24 26 + GND
4.7uF C5 + VPP VPN GND TCK TDO TDI TMS TRST
4.7uF C6
4.7uF (low ESR, <1W, Tantalum, 25V or greater rating) *Not required if header is not installed.
VCC
FTSH-113-01-L-D-K
SAMTEC
The programming header is optional. It provides a means for re-programming the chip on board if necessary. The SAMTEC header has a notch and should be laid out in such a way that the notch is on the pin1 side. The header specified here is a thru-hole part and surface mount versions are available. Please refer to www.samtec.com for more information on the header.
Ordering Information
SM3E-XXX.XXM Replace XXX.XX with one of the following available frequencies, 012.96MHz, 019.44MHz, 025.92MHz, 038.88MHz, 051.84MHz or 077.76MHz. Please contact Connor-Winfield for other frequencies that may be available. Similar Products from Connor-Winfield SM3-XXX.XXM - Stratum 3 module with 4 input references. SM3-8R-XXX.XXM - Stratum 3 module with 8 input references. SM3-IT-XXX.XXM - Industrial temperature rated Stratum 3 module with 4 input references.
Data Sheet #: TM054
Page 35 of 36 Rev: 02 Date: 11/07/08
(c) Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
2111 Comprehensive Drive Aurora, Illinois 60505 Phone: 630- 851- 4722 Fax: 630- 851- 5040 www.conwin.com
Revision
00 01 02
Revision Date
03/31/05 08/11/05 11/07/08
Note
Final Release Data Sheet Corrected Typographical Errors Added Input Pulse Width Spec to Table 1

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