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copyright ? 201 3 future technology devices international limited 1 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 future technology devices international ltd . ft231x ( usb to full handshake uart ic ) the ft231x is a usb to serial uart interface with full modem control and the following advanced features: ? single chip usb to asynchronous serial data transfer interface. ? entire usb protocol handled on th e chip . no usb specific firmware programming required. ? fully integrated 2048 byte multi - time - programmable (mtp) memory, storing device descriptors and cbus i/o configuration. ? fully integrated clock generation with no external crystal required plus optional clock output selection enabling glue - less interface to external mcu or fpga. ? data transfer rates from 300 baud to 3 mbaud (rs422 , rs485 , and rs232 ) at ttl levels . ? 512 byte receive buffer and 512 byte transmit buffer utilising buffer smoothing technology to allow for high data throughput. ? ftdis royalty ? configurable cbus i/o pins. ? transmit and receive led drive signals. ? uart interface support for 7 or 8 data bits, 1 or 2 stop bits and odd / even / mark / space no parity ? synchronous and asynchronous bit bang interface options with rd# and wr# strobes . ? u sb battery charge r detection . allows for usb peripheral devices to detect the presence of a higher power source to enable improved charging . ? device supplied pre - programmed with unique usb serial number. ? usb power configurations; s upports bus - powered, self - powered and bus - powered with power switching ? integrated + 3.3v level converter for usb i/o . ? true 3.3v cmos drive output and ttl input ; operates down to 1v8 with external pull - ups . tolerant of 5v input. ? configurable i /o pin output drive strength ; 4 ma(min) and 16 ma(max) . ? integrated power - on - reset circuit. ? fully integrated avcc supply filtering - no external filter ing required. ? uart signal inversion option . ? + 5v single supply operation. ? internal 3v3/1v8 ldo regulators low operating and usb suspend current ; 8 ma (active - typ) and 125 ua (sus pend - typ) . ? uhci/ohci/ehci host controller compatible ? usb 2.0 full speed capable. ? e xtended operating temperature range ; - 40 to 85 ? ? available in compact , pb - free , 20 pin ssop and qfn packages (both rohs compliant) . neither the whole nor any part of the information contained in, or the product described in thi s manual, may be adapted or reproduced in any material or electronic form without the prior written consent of the copyright holder. this product and its documentat ion are supplied on an as - is basis and no warranty as to their suitability for any particula r purpose is either made or implied. future technology devices international ltd will not accept any claim for damages howsoever arising as a result of use or failure of this produ ct. your statutory rights are not affected. this product or any variant of i t is not intended for use in any medical appliance, device or system in which the failure of the product might reasonably be expected to result in personal injury. this document provides preliminar y information that may be subject to change without notice. no freedom to use patents or other intellectual property rights is implied by the publication of this document. future technology devices international ltd, unit 1, 2 seaward place, centurion business park , glasgow g41 1hh united kingdom. scotland registe red company number: sc136640
copyright ? 201 3 future technology devices international limited 2 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 1 typical applications ? usb to rs232/rs422/rs485 converters ? upgrading legacy peripherals to usb ? utilising usb to add system modularity ? incorporate usb interface to enable pc transfers for development system communication ? cellular and cordless phone usb data transfer cables and interfaces ? i nterfacing mcu / pld/fpga based designs to add usb connectivity ? usb audio and low bandwidth video data transfer ? u sb smart card readers ? usb instrumentation ? usb industrial control ? usb mp3 player interface ? usb flash card reader and writers ? set top box pc - usb interface ? usb digital camera interface ? usb hardware modems ? usb wireless modems ? usb bar code readers ? usb dongle implementations for software / hardware encryption and wireless modules ? de tection of dedicated battery charger ports for high current charging of batteries in portable devices. 1.1 driver support royalty free virtual com port (vcp) drivers for... ? windows 8 32,64 - bit ? windows 7 32,64 - bit ? windows xp and xp 64 - bit ? windows vista and vista 64 - bit ? windows xp embedded ? windows ce 4.2, 5.0 and 6.0 ? mac os - x ? linux 3.2 and greater ? android royalty free d2xx direct drivers (usb drivers + dll s/w interface) ? windows 8 32,64 - bit ? windows 7 32,64 - bit ? windows xp and xp 64 - bit ? windows vista and vista 64 - bit ? windows xp embedded ? windows ce 4.2, 5.0 and 6.0 ? mac os - x ? linux 2. 6 and greater ? android the drivers listed above are all available to download for free from ftdi website ( www.ftdichip.com ) . various 3rd party drivers are also available for other operating systems - see ftdi website ( www.ftdichip.com ) for details. for driver installation, please refer to http://www.ftdichip.com/documents/installguides.htm 1.2 part numbers part number package ft231x q - x 20 pin qfn ft231xs - x 20 pin ssop note: packing codes for x is: - r: taped and reel, (ssop is 2 ,000pcs per reel, qfn is 5 ,000pcs per reel). - u : t ube packing , 58 pcs per tube (ssop only) - t : tray packing , 490pcs per tray (qfn only) for example: ft231x q - r is 5 ,000pcs taped and reel packing
copyright ? 201 3 future technology devices international limited 3 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 1.3 usb compliant the ft231x is fully compliant with the usb 2.0 specification and has been given the usb - if test - id (tid) 4000 1464 (rev d ).
copyright ? 201 3 future technology devices international limited 4 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 2 ft231x block diagram figure 2 . 1 ft231x block diagram for a description of each function please refer to section 4. 3 . 3 v o l t l d o r e g u l a t o r 1 . 8 v o l t l d o r e g u l a t o r u s b t r a n s c e i v e r w i t h i n t e g r a t e d 1 . 5 k p u l l u p s a n d b a t t e r y c h a r g e d e t e c t i o n u s b d p l l i n t e r n a l 1 2 m h z o s c i l l a t o r x 4 c l o c k m u l t i p l i e r s e r i a l i n t e r f a c e e n g i n e ( s i e ) u s b p r o t o c o l e n g i n e u a r t f i f o c o n t r o l l e r u a r t c o n t r o l l e r w i t h p r o g r a m m a b l e s i g n a l i n v e r s i o n b a u d r a t e g e n e r a t o r r e s e t g e n e r a t o r f i f o t x b u f f e r ( 5 1 2 b y t e s ) f i f o r x b u f f e r ( 5 1 2 b y t e s ) i n t e r n a l m t p m e m o r y 4 8 m h z g n d r e s e t # t o u s b t r a n s c e i v e r c e l l 3 v 3 o u t 4 8 m h z 3 v 3 o u t v c c u s b d p u s b d m 1 v 8 i n t e r n a l c o r e s u p p l y t x d r x d r t s # c t s # d t r # d s r # d c d # r i # c b u s 0 c b u s 1 c b u s 2 c b u s 3
copyright ? 201 3 future technology devices international limited 5 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 table of contents 1 typical applications ................................ ................................ ...... 2 1.1 driver support ................................ ................................ .................... 2 1.2 part n umbers ................................ ................................ ...................... 2 1.3 usb compliant ................................ ................................ .................... 3 2 ft231x block diagram ................................ ................................ . 4 3 device pin out and signal description ................................ .......... 7 3.1 20 - ld qfn package ................................ ................................ ........... 7 3.1.1 qfn package pinout description ................................ ................................ .................... 7 3.2 20 - ld ssop package ................................ ................................ .......... 9 3.2.1 ssop package pinout description ................................ ................................ .................. 9 3.3 cbus signal options ................................ ................................ ......... 10 4 function description ................................ ................................ ... 13 4.1 key features ................................ ................................ ..................... 13 4.2 functional block descriptions ................................ ........................... 13 5 devices characteristics and ratings ................................ ........... 16 5.1 absolute maximum ratings ................................ ............................... 16 5.2 esd and latch - up specifications ................................ ....................... 16 5.3 dc characteristics ................................ ................................ ............. 17 5.4 mtp memory reliability characteristics ................................ ............ 21 5.5 internal clock characteristics ................................ ........................... 21 6 usb power configurations ................................ .......................... 22 6.1 usb bus powered configuration ................................ ...................... 22 6.2 self powered configuration ................................ .............................. 23 6.3 usb bus powered with power switching configuration .................... 24 7 application examples ................................ ................................ . 25 7.1 usb to rs232 converter ................................ ................................ ... 25 7.2 usb to rs485 coverter ................................ ................................ ..... 26 7. 3 usb to rs422 converter ................................ ................................ ... 27 7.4 usb battery charging detection ................................ ....................... 28 7.5 led interface ................................ ................................ .................... 30 8 internal mtp memory configuration ................................ ........... 32 8.1 default values ................................ ................................ .................. 32 8.2 methods of programming the mtp memory ................................ ....... 34 8.2.1 programming the mtp memory over usb ................................ ................................ ...... 34 8.3 memory map ................................ ................................ ..................... 34
copyright ? 201 3 future technology devices international limited 6 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9 package parameters ................................ ................................ ... 36 9.1 ssop - 20 package mechanical dimensions ................................ ........ 36 9.2 ssop - 20 package markings ................................ .............................. 37 9.3 qfn - 20 package mechanical dimensions ................................ .......... 38 9.4 qfn - 20 package markings ................................ ................................ 39 9.5 solder reflow profile ................................ ................................ ........ 40 10 contact information ................................ ................................ ... 41 appendix a C references ................................ ................................ ........... 42 appendix b C list of figures and tables ................................ .................... 42 appendix c C revision history ................................ ................................ ... 44
copyright ? 201 3 future technology devices international limited 7 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 3 device pin out and signal description 3.1 20 - ld qfn package figure 3 . 1 qfn schematic symbol 3.1.1 qfn package pin out description note: # denotes an active low signal. pin no. name type description 12 ** vcc power input 5 v or 3v3 supply to ic 20 vccio power input 1v8 C 3v3 supply for the io cells 10 ** 3v3out power output 3v3 output at 50ma. may be used to power vccio . when vcc is 3v3 ; pin 10 is an input pin and should be connected to pin 12 . 3, 13 gnd power input 0v ground input. table 3 . 1 power and ground *pin 21 on the symbol is the pad under the centre of the chip package and should be connected to gnd ** if vcc is 3v3 then 3v3out must also be driven with 3v3 input v c c i o 2 0 ri# 2 dtr# 18 g n d 3 dsr# 4 rts# 19 cts# 6 cbus2 7 usbdp 8 usbdm 9 3v3out 10 reset# 11 v c c 1 2 cbus1 14 cbus0 15 g n d 1 3 txd 17 dcd# 5 rxd 1 cbus3 16 g n d 2 1
copyright ? 201 3 future technology devices international limited 8 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 pin no. name type description 9 usb dm input usb data signal minus. 8 usb dp input usb data signal plus. 11 reset# input reset input (active low). table 3 . 2 common function pins pin no. name type description 17 txd output transmit asynchronous data output. 1 rxd input receiving asynchronous data input. 19 rts# output request to send control output / handshake signal. 6 cts# input clear to send control input / handshake signal. 18 dtr# output data terminal ready control output / handshake signal. 4 dsr# input data set ready control input / handshake signal. 5 dcd# input data carrier detect control input. 2 ri# input ring indicator input for remote wake up. 15 cbus0 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is txden . see cbus signal options, table 3 . 7 . 14 cbus1 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is rxled# . see cbus signal options, table 3 . 7 . 7 cbus2 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is txled# . see cbus signal options, table 3 . 7 . 16 cbus3 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is sleep# . see cbus signal options, table 3 . 7 . table 3 . 3 uart interface and cbus group (see note 1 ) notes: 1 when used in input mode, the input pins are pulled to vccio via internal 75k (approx) resistors. these pins can be programmed to gently pull low during usb suspend (pwren# = 1) by setting an option in the mtp memory .
copyright ? 201 3 future technology devices international limited 9 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 3.2 20 - ld ssop package figure 3 . 2 ssop schematic symbol 3.2.1 ssop package pin out description note: # denotes an active low signal. pin no. name type description 15 ** vcc power input 5 v or 3v3 supply to ic 3 vccio power input 1v8 C 3v3 supply for the io cells 1 3 ** 3v3out power output 3v3 output at 50ma. may be used to power vccio . when vcc is 3v3, pin 13 is an input pin. 6, 16 gnd power input 0v ground input. table 3 . 4 power and ground ** if vcc is 3v3 then 3v3out must also be driven with 3v3 input pin no. name type description 1 2 usb dm input usb data signal minus. 1 1 usb dp input usb data signal plus. 14 reset# input reset input (active low). table 3 . 5 common function pins rxd 4 ri# 5 g n d 6 dsr# 7 dcd# 8 cts# 9 cbus2 10 usbdp 11 usbdm 12 3v3out 13 reset# 14 v c c 1 5 g n d 1 6 cbus1 17 cbus0 18 cbus3 19 txd 20 dtr# 1 rts# 2 v c c i o 3
copyright ? 201 3 future technology devices international limited 10 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 pin no. name type description 20 txd output transmit asynchronous data output. 4 rxd input receiving asynchronous data input. 2 rts# output request to send control output / handshake signal. 9 cts# input clear to send control input / handshake signal. 1 dtr# output data terminal ready control output / handshake signal. 7 dsr# input data set ready control input / handshake signal. 8 dcd# input data carrier detect control input. 5 ri# input ring indicator input for remote wake up. 1 8 cbus0 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is txden . see cbus signal options, table 3 . 7 . 1 7 cbus1 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is rxled# . see cbus signal options, table 3 . 7 . 10 cbus2 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is txled# . see cbus signal options, table 3 . 7 . 19 cbus3 i/o configurable cbus i/o pin. function of this pin is configured in the device mtp memory . t he default configuration is sleep# . see cbus signal options, table 3 . 7 . table 3 . 6 uart interface and cbus group (see note 1 ) notes: 1 when used in input mode, the input pins are pulled to vccio via internal 75k (approx) resistors. these pins can be programmed to gently pull low during usb suspend (pwren# = 1) by setting an option in the mtp memory . 3.3 cbus signal options
copyright ? 201 3 future technology devices international limited 11 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 the following options can be configured on the cbus i/o pins. cbus signal options are common to both package versions of the ft231x . these options can be configured in the internal mtp memory using the software utility ft_p prog, which can be downloaded from the ftdi utilities ( www.ftdichip.com ) . the default configuration is described in s ection 8 . cbus signal option available on cbus pin description tri - state cbus0, cbus1, cbus2, cbus3 io pad is tri - stated drive 1 cbus0, cbus1, cbus2, cbus3 output a constant 1 drive 0 cbus0, cbus1, cbus2, cbus3 output a constant 0 txden cbus0, cbus1, cbus2, cbus3 enable transmit data for rs485 pwren# cbus0, cbus1, cbus2, cbus3 output is low after the device has been configured by usb, then high during usb suspend mode. this output can be use d to control power to external logic p - channel logic level mosfet switch. enable the interface pull - down option when using the pwren# in this way. txled# cbus0, cbus1, cbus2, cbus3 transmit data led drive C pulses low when transmitting data via usb. see s ection 7.5 for more details. rxled# cbus0, cbus1, cbus2, cbus3 receive data led drive C pulses low when receiving data via usb. see section 7.5 for more details. tx&rxled# cbus0, cbus1, cbus2, cbus3 led drive C pulses low when transmitting or receiving data via usb. see section 7.5 for more details. sleep# cbus0, cbus1, cbus2, cbus3 goes low during usb suspend mode. typically used to power down an external ttl to rs 232 level converter ic in usb to rs232 converter designs. clk24 mhz cbus0, cbus1, cbus2, cbus3 24 mhz clock output.* clk12 mhz cbus0, cbus1, cbus2, cbus3 12 mhz clock output.* clk6 mhz cbus0, cbus1, cbus2, cbus3 6 mhz clock output.* gpi o cbus0, cbus1, cbus2, cbus3 cbus bit bang mode option. allows up to 4 of the cbus pins to be used as general purpose i/o. configured individually for cbus0, cbus1, cbus2 and cbus3 in the internal mtp memory . a separate application note, an232r - 01 , available from ftdi website ( www.ftdichip.com ) describes in more detail how to use cbus bit bang mode. bcd charger cbus0, cbus1, cbus2, cbus3 battery c harge detect, indicates when the device is connected to a dedicated battery charger. active high output. bcd charger # cbus0, cbus1, cbus2, cbus3 inverse of bcd charger bitbang_wr# cbus0, cbus1, cbus2, cbus3 synchronous and asynchronous bit bang mode wr# strobe output. bitbang_rd# cbus0, cbus1, cbus2, cbus3 synchronous and asynchronous bit bang mode rd# strobe output. vbus sense cbus0, cbus1, cbus2, cbus3 input to detect when vbus is present.
copyright ? 201 3 future technology devices international limited 12 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 cbus signal option available on cbus pin description time stamp cbus0, cbus1, cbus2, cbus3 toggle signal which changes state each time a usb sof is received keep_awake# cbus0, cbus1, cbus2, cbus3 prevents the device from entering suspend state when unplugged. table 3 . 7 cbus configuration control *when in usb suspend mode the outputs clocks are also suspended.
copyright ? 201 3 future technology devices international limited 13 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 4 function description the ft231x is a usb to full handshake serial uart interface device which simplifies usb implementations and reduces ext ernal component count by fully integrating an mtp memory , and an integrated clock circuit which requires no external crystal . it has been designed to operate efficiently with usb host controller s by using as little bandwidth as possible when compared to the total usb bandwidth available. 4.1 key features functional integration. fully integrated mtp memory , clock generation, avcc filtering, p ower - on - reset (p or ) and ldo regulator s . configurable cbus i/o pin options. the fully integrated mtp memory allows configuration of the control bus (cbus) functionality and drive strength selection. there are 4 configurable cbus i/o pins. these configurable options are detailed in section 3.3 the cbus l ines can be configured with any one of these output options by setting bits in the internal mtp memory . the device is s hipped with the most commonly used pin definitions pre - programmed C see section 8 for details. asynchronous bit bang mode with rd# and wr# strobes. the ft231x supports ftdis previous chip generation bit - bang mode. in bit - bang mode, the eight uart lines can be switched fro m the regular interface mode to an 8 - bit general purpose i/o port. data packets can be sent to the device and they will be sequentially sent to the interface at a rate controlled by an internal timer (equivalent to the baud rate pre - scalar ). in t he ft231x device this mode has been enhanced by outputting the internal rd# and wr# strobes signals which can be used to allow external logic to be clocked by accesses to the bit - bang i/o bus. this option will be described more fully in a separate applicat ion note available from ftdi website ( www.ftdichip.com ) . synchronous bit bang mode. the ft231x supports synchronous bit bang mode. this mode differs from asynchronous bit bang mode in that the interface pins are only read when the device is written to. this makes it easier for the controlling program to measure the response to an output stimulus as the data returned is synchronous to the output data. an application note, an232r - 01 , available from ftdi website ( www.ftdichip.com ) describes this feature. source power and power consumption . the ft231x is capable of operating at a voltage supply between + 3.3 v and +5 .25 v with a nominal operational mode current of 8 ma and a nominal usb suspend mode current of 125 a. this allows greater margin for peripheral designs to meet the usb suspend mode current limit of 2.5ma . an integrated level converter within the uart interface allows the ft231x to interface to uart logic running at +1.8v to +3.3v (5v tol erant ). 4.2 functional block descriptions the following paragraphs detail each function within the ft231x . please refer to the block diagram shown in figure 2.1 internal mtp m emory . the internal mtp memory in the ft231x is used to store usb vendor id (vid), product id (pid), device serial number, product description string and various other usb configuration descriptors. the internal mtp memory is also used to configure the cbus pin functions. the ft231x is supplied with the int ernal mtp memory pre - programmed as described in section 8 . a user area of the internal mtp memory is available to system designers to allow storing additional data from the user application over usb . the internal mtp memory descriptors can be programmed in circuit, over usb without any additional voltage requirement. the descriptors can be programmed using th e ftdi utility software called ft_ prog, which can be d ownloaded from ftdi utilities on the ftdi website ( www.ftdichip.com ) . +3.3v ldo regulator. the +3.3v ldo regulator g enerates the +3.3v reference voltage for driving the usb transceiver cell output buffers. it requires an external decoupling capacitor to be attached to the 3v3out regulator output pin. it also provides +3.3v power to the 1.5k internal pull up resistor on usbdp. the main function of the ldo is to power the usb transceiver and the reset generator cells rather than to power external logic. however, it can be used to supply external circuitry requiring a +3.3v nominal supply with a maximum current of 50ma . +1.8 v ldo regulator. the + 1.8 v ldo regulator generates the + 1.8 v reference voltage for internal use driving the ic core functions of the serial interface engine and usb protocol engine.
copyright ? 201 3 future technology devices international limited 14 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 usb transceiver. the usb transceiver cell provides the usb 1.1 / usb 2.0 full - speed physical interface to the usb cable. the output drivers provide +3.3v level slew rate control signalling, whilst a differential input receiver and two single ended input receivers provide usb data in, single - ended - 0 (se0) and usb reset detec tion conditions respectfully. this function also incorporates a 1.5k pull up resistor on usbdp. the block also detects when connected to a usb power supply which will not enumerate the device but still supply power and may be used for battery charging . us b dpll. the usb dpll cell locks on to the incoming nrzi usb data and generates recovered clock and data signals for the serial interface engine (sie) block. internal 12mhz oscillator C the internal 12mhz oscillator cell generates a 12mhz reference clock. this provides an input to the x4 clock multiplier function. the 12mhz oscillator is also used as the reference clock for the sie, usb protocol engine and uart fifo controller blocks. clock multiplier / divider. the clock multiplier / divider takes the 12mh z input from the internal oscillator function and generates the 48mhz, 24mhz, 12mhz and 6mhz reference clock signals. the 48mz clock reference is used by the usb dpll and the baud rate generator blocks. serial interface engine (sie). the serial interface e ngine (sie) block performs the parallel to serial and serial to parallel conversion of the usb data. in accordance with the usb 2.0 specification, it performs bit stuffing/un - stuffing and crc5/crc16 generation. it also verifies the crc on the usb data stream. usb protocol engine. the usb protocol engine manages the data stream from the device usb control endpoint. it handles the low level usb protocol requests generated by the usb host controller and the commands for controlling the functional parameters of the uart in accordance with the usb 2.0 specification chapter 9. fifo r x buffer (512 bytes). data sent from the usb host controller to the uart via the usb data out endpoint is stored in the fifo rx (receive) buffer. data is removed from the buffer to the uart transmit register under control of the uart fifo controller. (rx relative to the usb interface). fifo t x buffer (512 bytes). data from the uart receive register is stored in the t x buffer . the usb host controller removes data from the fi fo tx buffer by sending a usb request for data from the device data in endpoint. (tx relative to the usb interface). uart fifo controller. the uart fifo controller handles the transfer of data between the fifo rx and tx buffers and the uart transmit and receive registers. uart controller with programmable signal inversion and high drive. together with the uart fifo controller the uart controller handles the transfer of data between the fifo rx and fifo tx buffers and the uart transmit and receive registers. it performs asynchronous 7 or 8 bit parallel to serial and serial to parallel conve rsion of the data on the rs232 (or rs422 or rs485) interface. control signals supported by uart mode include rts, cts, dsr, dtr, dcd and ri. the uart controller also provides a transmitter enable control signal pin option ( txden ) to assist with interfacin g to rs485 transceivers. rts/cts, dsr/dtr and x on / x off handshaking options are also supported. handshaking is handled in hardware to ensure fast response times. the uart interface also supports the rs232 break setting and detection conditions. additiona lly, the uart signals can each be individually inverted and have a configurable high drive strength capability. both these features are configurable in the mtp memory . baud rate generator C the baud rate generator provides a 16x clock input to the uart c ontroller from the 48mhz reference clock. it consists of a 14 bit pre - scalar and 3 register bits which provide fine tuning of the baud rate (used to divide by a number plus a fraction or sub - integer). this determines the baud rate of the uart, whic h is programmable from 183 baud to 3 mbaud. the ft231x supports all standard baud rates and non - standard baud rates from 183 baud up to 3 mbaud. achievable non - standard baud rates are calculated as follows C baud rate = 3000000 / (n + x ) where n can be any integer between 2 and 16,384 ( = 2 14 ) and x can be a sub - integer of the value 0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, or 0.875. when n = 1, x = 0, i.e. baud rate divisors with values between 1 and 2 are not possible. this gives achievable baud r ates in the range 183.1 baud to 3,000,000 baud. when a non - standard baud rate is required simply pass the required baud rate value to the driver as normal, and the ftdi driver will calculate the required divisor, and set the baud rate. see ftdi application note an232b - 05 on the ftdi website ( www.ftdichip.com ) for more details.
copyright ? 201 3 future technology devices international limited 15 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 reset generator C the integrated reset generator cell provides a reliable power - on reset to the device internal circuitry at power up. the reset# input pin allows an external device to reset the ft231x . reset# can be tied to 3v3out .
copyright ? 201 3 future technology devices international limited 16 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 5 devices characteristics and ratings 5.1 absolute maximum ratings the absolute maximum ratings for the ft231x devices are as follows. these are in accordance with the absolute maximum rating system (iec 60134). exceeding these may cause permanent damage to the device. parameter value unit conditions storage temperature - 65c to 150c degrees c floor life (out of bag) at factory ambient (30c / 60% relative humidity) 168 hours (ipc/jedec j - std - 033a msl level 3 compliant)* hours ambient operating temperature (power applied) - 40c to 85c degrees c mttf ft2 31 x s tbd hours mttf ft2 31 x q tbd hours vcc supply voltage - 0.3 to +5 . 5 v vccio io voltage - 0.3 to +4.0 v dc input voltage C usbdp and usbdm - 0.5 to +3.63 v dc input voltage C high impedance bi - directionals (powered from vccio) - 0.3 to +5.8 v dc output current C outputs 22 ma esd charge device mode(cdm) 500 v class iii esd human body mode (hdm) 2000 v class 2 table 5 . 1 absolute maximum ratings * if devices are stored out of the packaging beyond this time limit the devices should be baked before use. the devices should be ramped up to a temperature of + 125 c and baked for up to 17 hours . 5.2 esd and latch - up specifications description specification human body mode (hbm) > 2kv machine mode (mm) > 200v charged device mode (cdm) > 500v latch - up > 200ma table 5 . 2 esd and latch - up specifications
copyright ? 201 3 future technology devices international limited 17 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 5.3 dc characteristics dc characteristics (ambient temperature = - 40c to + 85c ) parameter description minimum typical maximum units conditions vcc vcc operating supply voltage 2.97 5 5.5 v normal operation vcc 2 vccio operating supply voltage 1.62 --- 3.63 v icc1 operating supply current 8 8 8.4 ma normal operation icc2 operating supply current 125 a table 5 . 3 operating voltage and current
copyright ? 201 3 future technology devices international limited 18 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 parameter description minimum typical maximum units conditions voh output voltage high 2.97 vccio vccio v ioh = +/ - 2ma i/o drive strength* = 4ma 2.97 vccio vccio v i/o drive strength* = 8ma 2.97 vccio vccio v i/o drive strength* = 12ma 2.97 vccio vccio v i/o drive strength* = 16ma vol output voltage low 0 0.4 v iol = +/ - 2ma i/o drive strength* = 4ma 0 0.4 v i/o drive strength* = 8ma 0 0.4 v i/o drive strength* = 12ma 0 0.4 v i/o drive strength* = 16ma vil input low switching threshold 0.8 v lvttl vih input high switching threshold 2.0 v lvttl vt switching threshold 1. 49 v lvttl vt - schmitt trigger negative going threshold voltage 1.1 5 v vt+ schmitt trigger positive going threshold voltage 1.6 4 v rpu input pull - up resistance 40 75 190 k? vin = 0 rpd input pull - down resistance 40 75 190 k? vin =vccio iin input leakage current - 10 +/ - 1 10 a vin = 0 ioz tri - state output leakage current - 10 +/ - 1 10 a vin = 5.5v or 0 table 5 . 4 i/o pin characteristics vccio = +3.3v (except usb phy pins) * the i/o drive strength and slow slew - rate are configurable in the mtp memory .
copyright ? 201 3 future technology devices international limited 19 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 parameter description minimum typical maximum units conditions voh output voltage high 2.25 vccio vccio v ioh = +/ - 2ma i/o drive strength* = 4ma 2.25 vccio vccio v i/o drive strength* = 8ma 2.25 vccio vccio v i/o drive strength* = 12ma 2.25 vccio vccio v i/o drive strength* = 16ma vol output voltage low 0 0.4 v iol = +/ - 2ma i/o drive strength* = 4ma 0 0.4 v i/o drive strength* = 8ma 0 0.4 v i/o drive strength* = 12ma 0 0.4 v i/o drive strength* = 16ma vil input low switching threshold 0.8 v lvttl vih input high switching threshold 0.8 v lvttl vt switching threshold 1.1 v lvttl vt - schmitt trigger negative going threshold voltage 0.8 v vt+ schmitt trigger positive going threshold voltage 1. 2 v rpu input pull - up resistance 40 75 190 k? vin = 0 rpd input pull - down resistance 40 75 190 k? vin =vccio iin input leakage current - 10 +/ - 1 10 a vin = 0 ioz tri - state output leakage current - 10 +/ - 1 10 a vin = 5.5v or 0 table 5 . 5 i/o pin characteristics vccio = +2.5 v (except usb phy pins) * the i/o drive strength and slow slew - rate are configurable in the mtp memory .
copyright ? 201 3 future technology devices international limited 20 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 parameter description minimum typical maximum units conditions voh output voltage high 1.62 vccio vccio v ioh = +/ - 2ma i/o drive strength* = 4ma 1.62 vccio vccio v i/o drive strength* = 8ma 1.62 vccio vccio v i/o drive strength* = 12ma 1.62 vccio vccio v i/o drive strength* = 16ma vol output voltage low 0 0.4 v iol = +/ - 2ma i/o drive strength* = 4ma 0 0.4 v i/o drive strength* = 8ma 0 0.4 v i/o drive strength* = 12ma 0 0.4 v i/o drive strength* = 16ma vil input low switching threshold 0.77 v lvttl vih input high switching threshold 1.6 v lvttl vt switching threshold 0.77 v lvttl vt - schmitt trigger negative going threshold voltage 0.557 v vt+ schmitt trigger positive going threshold voltage 0.893 v rpu input pull - up resistance 40 75 190 k? vin = 0 rpd input pull - down resistance 40 75 190 k? vin =vccio iin input leakage current - 10 +/ - 1 10 a vin = 0 ioz tri - state output leakage current - 10 +/ - 1 10 a vin = 5.5v or 0 table 5 . 6 i/o pin characteristics vccio = +1.8 v (except usb phy pins) * the i/o drive strength and slow slew - rate are configurable in the mtp memory .
copyright ? 201 3 future technology devices international limited 21 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 parameter description minimum typical maximum units conditions voh output voltage high vcc - 0.2 v vol output voltage low 0.2 v vil input low switching threshold - 0.8 v vih input high switching threshold 2.0 - v table 5 . 7 usb i/o pin (usbdp, usbdm) characteristics 5.4 mtp m emory reliability characteristics the internal 2048 b yte mtp memory has the following reliability characteristics: parameter value unit data retention 1 0 years write cycle 2 ,000 cycles read cycle unlimited cycles table 5 . 8 mtp memory characteristics 5.5 internal clock characteristics the internal clock oscillator has the following characteristics: parameter value unit minimum typical maximum frequency of operation (see note 1) 11.98 12.00 12.02 mhz clock period 83.19 83.33 83.47 ns duty cycle 45 50 55 % table 5 . 9 internal clock characteristics note 1: equivalent to +/ - 1667ppm
copyright ? 201 3 future technology devices international limited 22 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 6 usb power configurations the following sections illustrate possible usb power configurations for the ft231x . the illustrations have omitted pin numbers for ease of understanding since the pins differ between the ft231xs and ft231x q package options. all usb power configurations illustrated apply to both package options for the ft231x device. please refer to section 9 for the package option pin - out and signal descriptions. 6.1 usb bus powered configuration figure 6 . 1 bus powered configuration figure 6 . 1 illustrates the ft231x in a typical usb bus powered design configuration. a usb bus powered device gets its power from the usb bus. basic rules for usb bus power devices are as follows C i) on p lug - in to usb, the device should draw no more current than 100ma. ii) in usb suspend mode the device should draw no more than 2.5ma . iii) a bus powered high power usb device (one that draws more than 100ma) should use one of the cbus pins configured as pwren# and u se it to keep the current below 100ma on plug - in and 2.5ma on usb suspend. iv) a device that consumes more than 100ma cannot be plugged into a usb bus powered hub. v) no device can draw more than 500ma from the usb bus. the power descriptors in the internal mtp m emory of the ft231x should be programmed to match the current drawn by the device. a ferrite bead is connected in series with the usb power supply to reduce emi noise from the ft231x and associated circuitry being radiated down the usb cable to the usb hos t. the value of the ferrite bead depends on the total current drawn by the application. a suitable range of ferrite beads is available from laird technologies ( http://www.lairdtech.com ) , for example laird technologies part # mi0805k400r - 10. note: if using pwren# (available using the cbus) the pin should be pulled to vccio using a 10k resistor. f t 2 3 1 x 1 2 3 4 5 s h i e l d f e r r i t e b e a d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o v c c g n d g n d r e s e t # 1 0 0 n f 1 0 0 n f 1 0 n f 4 . 7 u f + 2 7 r 2 7 r g n d 4 7 p f 4 7 p f
copyright ? 201 3 future technology devices international limited 23 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 6.2 self powered configuration figure 6 . 2 self powered configuration figure 6 . 2 illustrates the ft231x in a typical usb self powered configuration. a usb self powered device gets its power from its own power supply, vcc, and does not draw current from the usb bus. the ba sic rules for usb self powered devices are as follows C i) a self powered device should not force current down the usb bus when the usb host or hub controller is powered down. ii) a self powered device can use as much current as it needs during normal operation a nd usb suspend as it has its own power supply. iii) a self powered device can be used with any usb host, a bus powered usb hub or a self powered usb hub. the power descriptor in the internal mtp memory of the ft231x should be programmed to a value of zero (self powered). in order to comply with the first requirement above, the usb bus power (pin 1) is used to control the vbus_sense pin of the ft220x device. when the usb host or hub is powered up an internal 1.5k resistor on usbdp is pulled up to +3.3v, thus ide ntifying the device as a full speed device to the usb host or hub. when the usb host or hub is powered off, vbus_sense pin will be low and the ft220x is held in a suspend state. in this state the internal 1.5k resistor is not pulled up to any power supply (hub or host is powered down), so no current flows down usbdp via the 1.5k pull - up resistor. failure to do this may cause some usb host or hub controllers to power up erratically . figure 6 . 2 illustrates a self powered design which has a + 3.3 v to +5 .25 v supply. note: 1. when the ft231x is in reset, the uart interface i/o pins are tri - stated. input pins have internal 200k pull - up r esistors to vccio, so they will gently pull high unless driven by some external logic. f t 2 3 1 x 1 2 3 4 5 s h i e l d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o v c c ( 3 . 3 - 5 . 2 5 v ) a g n d g n d v b u s _ s e n s e 1 0 0 n f 1 0 0 n f 1 0 0 n f 4 . 7 u f + g n d 4 k 7 1 0 k 4 7 p f g n d 4 7 p f 2 7 r 2 7 r r e s e t #
copyright ? 201 3 future technology devices international limited 24 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 6.3 usb bus powered with power switching configuration figure 6 . 3 bus powered with power switching configuration a requirement of usb bus powered applications, is when in usb suspend mode, the application draws a total current of less than 2.5ma . this requirement includes external logic. some external logic has the ability to power itself down into a low current state by monitoring the pwren# signal. for external logic that cannot power itself down in this way, the ft231x provides a simple but effective method of turning off power during the usb suspend mode. figure 6 . 3 shows an example of using a discrete p - channel mosfet to control the power to external logic. a suitable device to do this is an international rectifier (www.irf.com) irlm l6402, or equivalent. it is recommended that a soft start circuit consisting of a 1k series resistor and a 0.1f capacitor is used to limit the current surge when the mosfet turns on. without the soft start circuit it is possible that the transient powe r surge, caused when the mosfet switches on, will reset the ft231x or the usb host/hub controller. the soft start circuit example shown in figure 6 . 3 powers up with a slew rate of approximaely12.5v/ms. thus supply voltage to external logic transitions from gnd to +5v in approximately 400 microseconds. as an alternative to the mosfet, a dedicated power switch ic with inbuilt soft - start can be used. a suitable power swi tch ic for such an application is the micrel ( www.micrel.com ) mic2025 - 2bm or equivalent. with power switching controlled designs the follo wing should be noted: i) the external logic to which the power is being switched should have its own reset circuitry to automatically reset the logic when power is re - applied when moving out of suspend mode. ii) set the pull - down on suspend option in the internal ft231x mtp memory . iii) one of the cbus pins should be configured as pwren# in the internal ft231x mtp memory , and used to switch the power supply to the external circuitry. this should be pulled high through a 10 k? resistor. iv) for usb high - power bus powered applications (one that consumes greater than 100ma, and up to 500ma of current from the usb bus), the power consumption of the application must be set in the max power field in the internal ft231x mtp memory . a high - power bus powered application uses the descriptor in the internal ft231x mtp memory to inform the system of its power requirements. v) pwren# gets its vcc from vccio. for designs using 3v3 logic, ensure vccio is not powered down using the external lo gic. in this case use the +3v3out. f t 2 3 1 x 1 2 3 4 5 s h i e l d f e r r i t e b e a d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o a g n d g n d r e s e t # 1 0 0 n f 1 0 0 n f 1 0 n f 4 . 7 u f + c b u s 3 p w r e n # 1 0 k 1 k s w i t c h e d 5 v p o w e r t o e x t e r n a l l o g i c 0 . 1 u f 0 . 1 u f p c h a n n e l p o w e r m o s f e t 2 7 r 2 7 r g n d 4 7 p f 4 7 p f
copyright ? 201 3 future technology devices international limited 25 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 7 application examples the following sections illustrate possible applications of the ft231x . the illustrations have omitted pin numbers for ease of understanding since the pins differ between the ft231xs and ft231x q packa ge options. 7.1 usb to rs232 converter figure 7 . 1 application example showing usb to rs232 converter an example of using the ft231x as a usb to rs232 converter is illustrated in f igure 7.1. in this application, a 3v3 ttl to rs232 level converter ic is used on the serial uart interface of the ft231x to convert the 3v3 levels of the ft231x to rs232 levels. this level shift can be done using line drivers from a variety of vendors e.g. zywyn. a useful feature on some of these devices is the shdn# pin which can be used to power down the device to a low quiescent current during usb suspend mode. a suitable level shifting device is the zywyn zt 324 3f which is capable of rs232 communication at up to 10 00k baud. in example shown, the cbus0 and cbus1 have been configured as txled# and rxled# and are being used to drive two leds. f t 2 3 1 x 1 2 3 4 5 s h i e l d f e r r i t e b e a d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o v c c a g n d g n d r e s e t # 1 0 0 n f 1 0 0 n f 1 0 n f 4 . 7 u f + s l e e p # c b u s 1 c b u s 2 t x d r x d r t s # c t s # d t r # d s r # d c d # r i # r s 2 3 2 l e v e l c o n v e r t e r t x d a t a r x d a t a r t s c t s d t r d s r d c d r i t x l e d r x l e d v c c v c c 2 7 0 r 2 7 0 r g n d r i d t r c t s t x d a t a r t s r x d a t a d s r d c d d b 9 m s h i e l d 1 0 5 9 4 8 3 7 2 6 1 s h d n # c b u s 0 t x d r x d r t s # c t s # d t r # r i # d c d # d s r # 2 7 r 2 7 r g n d 4 7 p f 4 7 p f n o t e : i f d e s i g n u s e s v c c i o < 3 v 3 t h e n 1 0 k p u l l u p t o v c c i o i s r e q u i r e d o n i o l i n e s
copyright ? 201 3 future technology devices international limited 26 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 7.2 usb to rs485 coverter figure 7 . 2 application example showing usb to rs485 converter an example of using the ft231x as a usb to rs485 converter is shown in figure 7.2. in this application, a 3v3 - ttl to rs485 level converter ic is used on the serial uart interface of the ft231x to convert the ttl levels of the ft231x to rs485 levels. this example uses the zywyn zt3485 device. equivalent devices are available from maxim and analogue devices. the zt3485 is a rs485 device in a compact 8 pin so p package. it has separate enables on both the transmitter and receiver. with rs485, the transmitter is only enabled when a character is being transmitted from the uart. the txden signal cbus pin option on the ft231x is provided for exactly this purpose an d so the transmitter enable is wired to cbus2 which has been configured as txden . similarly, cbus3 has been configured as pwren#. this signal is used to control the zt3485s receiver enable. the receiver enable is active low, so it is wired to the pwren# pin to disable the receiver when in usb suspend mode. cbus2 = txden and cbus3 = pwren# are the default device configurations of the ft231x pins. rs485 is a multi - drop network ; so many devices can communicate with each other over a two wire cable interface. the rs485 cable requires to be terminated at each end of the cable. a link (which provides the 120? termination) allows the cable to be terminated if the zt3485 is physicall y positioned at either end of the cable. in this example the data transmitted by the ft231x is also present on the receive path of the zt3485 .this is a common feature of rs485 and requires the application software to remove the transmitted data from the re ceived data stream. with the ft231x it is possible to do this entirely in hardware by modifying the example shown in figure 7 . 2 by logically oring the ft231x txden an d the zt3485 receiver output and connecting the output of the or gate to the rxd of the ft231x . note that the txden is activated 1 bit period before the start bit. txden is deactivated at the same time as the stop bit. this is not configurable. f t 2 3 1 x 1 2 3 4 5 s h i e l d f e r r i t e b e a d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o v c c a g n d g n d r e s e t # 1 0 0 n f 1 0 0 n f 1 0 n f 4 . 7 u f + t x d r x d g n d d b 9 m s h i e l d 1 0 p w r e n # v c c i o 1 0 k r s 4 8 5 l e v e l c o n v e r t e r v c c z t 3 4 8 5 e 5 1 2 3 4 l i n k 1 2 0 r 7 6 t x d e n 2 7 r 2 7 r 4 7 p f 4 7 p f g n d
copyright ? 201 3 future technology devices international limited 27 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 7.3 usb to rs422 converter figure 7 . 3 usb to rs422 converter configuration an example of using the ft231x as a usb to rs422 converter is shown in figure 7.3. in this application, two 3v3 - ttl to rs422 level converter i c s are used on the serial uart interface of the ft231x to convert the ttl levels of the ft231x to rs422 levels. there are many suitable level converter devices available. this example uses zywyn zt3491 devices which have enables on both the transmitter and receiver. since the zt3491 transmitter enable is active high, it is connected to a cbus pin in sleep# configuration. the zt3491 receiver enable is active low and is therefore connected to a cbus pin p wren# configuration. this ensures that when both the zt3 491 transmitters and receivers are enabled then the device is active, and when the device is in usb suspend mode, the zt3 491 transmitters and receivers are disabled. if a similar application is used, but the design is usb bus powered, it may be necessary to use a p - channel logic level mosfet (controlled by pwren#) in the vcc line of the zt3 491 devices to ensure that the usb standby current of 2.5ma is met. the zt3 491 is specified to transmit and receiv e data at a rate of up to 16 mbaud. in this example the maximum data rate is limited to 3 mbaud by the ft231x . f t 2 3 1 x 1 2 3 4 5 s h i e l d f e r r i t e b e a d g n d g n d v c c g n d v c c 3 v 3 o u t u s b d m u s b d p v c c i o v c c a g n d g n d r e s e t # 1 0 0 n f 1 0 0 n f 1 0 n f 4 . 7 u f + r s 4 2 2 l e v e l c o n v e r t e r v c c z t 3 4 9 1 5 3 4 7 6 t x d m t x d p r x d p r x d m 1 2 0 r 1 0 9 1 1 1 2 r s 4 2 2 l e v e l c o n v e r t e r z t 3 4 9 1 3 4 7 6 v c c v c c 1 0 k 2 5 1 2 0 r 1 1 1 2 9 1 0 r t s m r t s p c t s p c t s m g n d d b 9 m s h i e l d t x d m t x d p r x d p r x d m r t s m r t s p c t s p c t s m 2 r x d t x d r t s # c t s # p w r e n # s l e e p # g n d 4 7 p f 4 7 p f 2 7 r 2 7 r
copyright ? 201 3 future technology devices international limited 28 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 7.4 usb battery charging detection a recent addition to the usb specification ( http://www.usb.org/developers/devclass_docs/bcv1.2_011912.zip ) is to allow for additional charging profiles to be used for charging batteries in portable devices. these charging pr ofiles do not enumerate the usb port of the peripheral . the ft231x device will detect that a usb compliant dedicated charging port (dcp) is connected. once detected while in suspend mode, a battery charge detection signal is provided to allow external logic to switch to charging mode as opposed to operation mode . to use the ft231x with battery charging detection the cbus pins must be reprogrammed to allow for the bcd charger output to switch the external charger circuitry on. the c bus pins are configured in the internal mtp memory with the free utility ftprog . if the charging circuitry requires an active low signal to enable it, the cbus pin can be programmed to bcd charger# as an alternative. when connected to a usb compliant de dicated charging port (dcp, as opposed to a standard usb host) the device usb signals will be shorted together and the device suspended. the bcd charger signal will bring the ltc4053 out of suspend and allow battery charging to start. the cha r ge current in the example below is 1a as defined by the resistance on the prog pin. figure 7 . 4 usb battery charging detection (1 pin) alternatively the pwren# and sleep pins may be used to control the ltc4053 such that a battery may be charged from a standard host (low current) or from a dedicated charging port (high current). in such a design as shown below the charge current would need to be limited to 0.4a to ensure that the u sb host power limit is not exceeded. x - c h i p p i n f u n c t i o n e e p r o m s e t t i n g c b u s 0 b c d b a t t e r y o p t i o n s b a t t e r y c h a r g e r e n a b l e f o r c e p o w e r e n a b l e d e - a c t i c a t e s l e e p x g n d g n d 0 . 1 u f 0 . 1 u f g n d g n d 6 0 0 r / 2 a 1 0 n f v b u s 3 v 3 o u t 0 . 1 u f 0 r g n d s l d g n d 2 7 r 2 7 r v b u s 1 d - 2 d + 3 g n d 5 i d 4 c n u s b v c c 2 f a u l t 3 t i m e r 4 g n d 5 n t c 6 p r o g 7 s h d n 8 b a t 9 a c p r 1 0 c h r g 1 g n d 1 1 l t c 4 0 5 3 e d d g n d 3 v 3 o u t 3 v 3 o u t 4 . 7 u f 0 . 1 u f g n d v b u s v b u s g n d v b a t t g n d g n d 1 k 5 g n d 1 t b 3 . 5 m m v b u s v b u s n t c 0 . 1 u f g n d v b u s 1 u f 1 r g n d v b u s b c d 2 k 2 g n d j p 1 1 - 2 2 - 3 n c t e n a b l e d n c t a v a i l a b l e j p 1 s i p - 3 n t c g n d n c t d i s a b l e d ( d e f a u l t ) j u m p e r - 2 m m 4 k 3 2 1 % g n d d p d m 3 v 3 o u t r e s e t # v c c g n d c b u s 0 v c c i o f t 2 3 1 x b c d 1 a w h e n c o n n e c t e d t o a d e d i c a t e d c h a r g e r p o r t 0 a w h e n e n u m e r a t e d 0 a w h e n i n s l e e p 0 a w h e n n o t e n u m e r a t e d a n d n o t i n s l e e p + - n c t n . f .
copyright ? 201 3 future technology devices international limited 29 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 figure 7 . 5 usb battery charging detection (2 pin) in the example above the ft231x sleep pin is used to enable/disable the ltc4053, while the pwren# signal alters the charging current by altering the resistance on the ltc4053 prog pin. a third option shown i n the example below uses the sleep signal from the ft231x to enable / disable the battery charger. the bcd# and pwren# signals are then us ed to alter the resistance on the prog pin of the ltc4053 which controls the charge current drawn from the usb connector. x - c h i p p i n f u n c t i o n e e p r o m s e t t i n g c b u s 5 c b u s 6 s l e e p # p w r e n # b a t t e r y o p t i o n s b a t t e r y c h a r g e r e n a b l e f o r c e p o w e r e n a b l e d e - a c t i c a t e s l e e p x x x s l e e p # p w r e n # d p d m 3 v 3 o u t v c o r e r e s e t # v c c c b u s 6 c b u s 5 v c c i o u 1 f t 2 3 1 x 0 . 4 a w h e n c o n n e c t e d t o a d e d i c a t e d c h a r g e r p o r t g n d g n d 0 . 1 u f 0 . 1 u f g n d g n d 6 0 0 r / 2 a 1 0 n f v b u s 3 v 3 o u t 0 . 1 u f 0 r g n d s l d g n d 2 7 r 2 7 r v b u s 1 d - 2 d + 3 g n d 5 i d 4 c n u s b 3 v 3 o u t 3 v 3 o u t v b u s v b u s n . f . 1 6 k 5 1 % g n d 4 k 3 2 1 % p w r e n # 0 . 4 a w h e n e n u m e r a t e d 0 a w h e n i n s l e e p m o d e 0 . 1 a w h e n n o t e n u m e r a t e d a n d n o t i n s l e e p m o d e v c c 2 f a u l t 3 t i m e r 4 g n d 5 n t c 6 p r o g 7 s h d n 8 b a t 9 a c p r 1 0 c h r g 1 g n d 1 1 l t c 4 0 5 3 e d d g n d 4 . 7 u f 0 . 1 u f g n d v b u s v b u s g n d v b a t t g n d g n d 1 t b 3 . 5 m m n t c 0 . 1 u f g n d v b u s 1 u f 1 r g n d v b u s 2 k 2 g n d j p 1 1 - 2 2 - 3 n c t e n a b l e d n c t a v a i l a b l e j p 1 s i p - 3 n t c g n d n c t d i s a b l e d ( d e f a u l t ) j u m p e r - 2 m m 4 k 3 2 1 % + - n c t s l e e p #
copyright ? 201 3 future technology devices international limited 30 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 figure 7 . 6 usb battery charging detection (3 pin) to calculate the equivalent resistance on the ltc4053 prog pin select a charge current, then res = 1500v/i chg for more configuration options of the ltc4053 refer to: an_175_battery charging over usb note: if the ft231x is connected to a standard host po rt such that the device is enumerated the battery charge detection signal is inactive as the device will not be in suspend . 7.5 led interface any of the cbus i/o pins can be configured to drive an led. the ft231x has 3 configuration options for driving leds from the cbus. these are txled#, rxled#, and tx&rxled#. refer to section 3.3 for configuration options. x - c h i p p i n f u n c t i o n e e p r o m s e t t i n g c b u s 0 c b u s 1 c b u s 2 b c d # p w r e n # s l e e p # b a t t e r y o p t i o n s b a t t e r y c h a r g e r e n a b l e f o r c e p o w e r e n a b l e d e - a c t i c a t e s l e e p x x p w r e n # g n d c b u s 2 1 0 d p d m 3 v 3 o u t r e s e t # v c c g n d c b u s 1 1 7 c b u s 0 1 8 v c c i o f t 2 3 1 x b c d # s l e e p # g n d g n d 0 . 1 u f 0 . 1 u f g n d g n d 6 0 0 r / 2 a 1 0 n f v b u s 3 v 3 o u t 0 . 1 u f 0 r g n d s l d g n d 2 7 r 2 7 r v b u s 1 d - 2 d + 3 g n d 5 i d 4 c n u s b 3 v 3 o u t 3 v 3 o u t v b u s v b u s n . f . 1 k 5 - 1 % 1 6 k 5 1 % g n d b c d # 4 k 3 2 1 % p w r e n # 1 a w h e n c o n n e c t e d t o a d e d i c a t e d c h a r g e r p o r t 0 . 4 a w h e n e n u m e r a t e d 0 a w h e n i n s l e e p 0 . 1 a w h e n n o t e n u m e r a t e d a n d n o t i n s l e e p v c c 2 f a u l t 3 t i m e r 4 g n d 5 n t c 6 p r o g 7 s h d n 8 b a t 9 a c p r 1 0 c h r g 1 g n d 1 1 l t c 4 0 5 3 e d d g n d 4 . 7 u f 0 . 1 u f g n d v b u s v b u s g n d v b a t t g n d g n d 1 t b 3 . 5 m m n t c 0 . 1 u f g n d v b u s 1 u f 1 r g n d v b u s 2 k 2 g n d j p 1 1 - 2 2 - 3 n c t e n a b l e d n c t a v a i l a b l e j p 1 s i p - 3 n t c g n d n c t d i s a b l e d ( d e f a u l t ) j u m p e r - 2 m m 4 k 3 2 1 % + - n c t s l e e p #
copyright ? 201 3 future technology devices international limited 31 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 figure 7 . 7 dual led configuration an example of using the ft231x to drive leds is shown in figure 7 . 7 . in this application one of the cbus pins is used to indicate transmission of data (txled#) and another is used to indicate receiving data (rxled#). when data is being transmitted or received the respective pins will drive from tri - state to low in order to provide indication on the leds of data transfer. a digital one - shot is used so that even a small percentage of data transfer is visible to the end user. figure 7 . 8 single led configuration another example of using the ft231x to drive leds is shown in figure 7 . 8 . in this example one of the cbus pins is used to indicate when data is being transmitted or received by the device (tx&rxled). in this configuration the ft231x will drive only a single led. f t 2 3 1 x c b u s [ 0 . . . 3 ] c b u s [ 0 . . . 3 ] v c c i o t x t x l e d # r x l e d # r x 2 7 0 r 2 7 0 r f t 2 3 1 x c b u s [ 0 . . . 3 ] t x & r x l e d # 2 7 0 r v c c i o l e d
copyright ? 201 3 future technology devices international limited 32 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 8 internal mtp memory configuration the ft231x includes an internal mtp memory which holds the usb configuration descriptors, other configuration data for the chip and also user data areas. following a power - on reset or a usb reset the ft231x will scan its internal mtp memory and read the usb configuration descriptors stored there. in many cases, the default values programmed into the mtp memory will be suitable and no re - programming will be necessary. the defaults can be found in section 8.1 . the mtp memory in the ft231x can be programmed over usb if the values need to be changed for a particular application. further details of this are provided from section 0 onwards. users who do not have their own usb vendor id but who would like to use a unique product id in their design can apply to ftdi for a free block of unique pids. see tn_100 C usb vendor id/product id guidelines for more details . 8.1 default values the default fac tory programmed values of the internal mtp memory are shown in table 8 . 1 . parameter value notes usb vendor id (vid) 0403h ftdi default vid (hex) usb product ud (pid) 60 1 5 h ftdi default pid (hex) serial number enabled? yes serial number see note a unique serial number is generated and programmed into the mtp memory during device final test. pull down i/o pins in usb suspend disabled enabling this option will make the device pull down on the uart interface lines when in usb suspend mode ( pwren# is high). manufacturer name ftdi product description ft231x usb uart max bus power current 9 0ma power source bus powered device type ft231x usb version 0200 returns usb 2.0 device descript ion t o the host. note: the de vice is a usb 2.0 full speed device (12mb/s) as opposed to a usb 2.0 high speed device (480mb/s). remote wake up en abled taking ri# low will wake up the usb host contro ller from suspend in approximately 20 ms . dbus drive current strength 4ma options are 4ma, 8ma, 12ma, 16ma dbus slew rate slow options are slow or fast dbus schmitt trigger enable normal options are normal or schmitt
copyright ? 201 3 future technology devices international limited 33 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 parameter value notes cbus drive current strength 4ma options are 4ma, 8ma, 12ma, 16ma cbus slew rate slow options are slow or fast cbus schmitt trigger enable normal options are normal or schmitt load vcp driver enabled ** makes the device load the vc p driver interface for the device. cbus 0 txden default configuration of cbus 0 C C C C table 8 . 1 default internal mtp m emory configuration ** vcp disabled in rev b silicon in error .
copyright ? 201 3 future technology devices international limited 34 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 8.2 methods of programming the mtp memory 8.2.1 programming the mtp memory over usb the mtp memory on all ft - x devices can be programmed over usb. this method is the same as for the eeprom on other ftdi devices such as the ft232r. no additional hardware, connections or programming voltages are required. the device is simpl y connected to the host computer in the same way that it would be for normal applications, and the ft_prog utility is used to set the required options and program the device. the ft _ prog utility is provided free - of - charge from the ftdi website, and can be found at the link below. the user guide is also available at this link. http://www.ftdichip.com/support/utilities.htm#ft_prog additionally, d2xx commands can be used to program the mtp memory from within user applications. for more information on the commands available, please see the d2xx programmers guide below. http://www.ftdichip.com/support/documents/programguides/d2xx_programmer s_guide(ft_000071).p df 8.3 memory map the ft - x family mtp me mory has various areas which come under three main categories: ? user memory area ? configuration memory area (writable) ? configuration memory area (non - writable) memory area description word address user memory area 2 accessible via usb 0x3ff C 0x80 configuration memory area accessible via usb 0x7e C 0x50 configuration memory area can not be written 0x4e C 0x40 user memory area 1 accessible via usb 0x3e C 0x12 configuration memory area accessible via usb 0x10 C 0x00 figure 8 . 1 : simplified memory map for the ft - x user memory area the user memory areas are highlighted in green on the memory map. they can be read and written via usb on the ft231x. all locations within this range are freely programmab le; no areas have special functions and there is no checksum for the user area. note that the application should take into account the specification for the number of write cycles in section 5.4 if it will be writing to the mtp memory multiple times.
copyright ? 201 3 future technology devices international limited 35 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 configuration memory area (writable) this area stores the configuration data for the device, including the data which is returned to the host in the configuration descri ptors (e.g. the vid, pid and string descriptions) and also values which set the hardware configuration (the signal assigned to each cbus pin for example). these values can have a significant effect on the behaviour of the device. steps must be taken to en sure that these locations are not written to un - intentionally by an application which is intended to access only the user area. this area is included in a checksum which covers configuration areas of the memory, and so changing any val u e can also cause this checksum to fail. configuration memory area ( non - writable) this is a reserved area and the application should not write to this area of memory. any attempt to write these locations will fail.
copyright ? 201 3 future technology devices international limited 36 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9 package parameters the ft231x is available in two differen t packages. the ft231x s is the ssop - 20 option and the ft231x q is the qfn - 20 package option. the solder reflow profile for both packages is described in section 0 . 9.1 ssop - 2 0 package mechanical dimensions figure 9 . 1 ssop - 2 0 package dimensions the ft231x s is supplied in a rohs compliant 2 0 pin ssop package. the package is lead (pb) free and uses a green compound. the package is fully compliant with european union directive 2002/95/ec. this package is nominally 8.66 mm x 3.91 mm body ( 8.66 mm x 5.99 mm including pins). the pins are on a 0.6 3 5 mm pitch. the above mechanical drawing shows the ssop - 20 package. .
copyright ? 201 3 future technology devices international limited 37 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9.2 ssop - 20 package markings figure 9 . 2 ssop - 2 0 package markings the date code format is yyxx where xx = 2 digit week number, yy = 2 digit year number. this is followed by the revision number. the code xxxxxxxxxxxx is the manufacturing lot code. f t 2 3 1 x s 1 1 0 1 1 2 0 - b
copyright ? 201 3 future technology devices international limited 38 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9.3 qfn - 20 package mechanical dimensions figure 9 . 3 qfn - 2 0 package dimensions the ft231x q is supplied in a rohs compliant leadless qfn - 20 package. the package is lead ( pb ) free, and uses a green compound. the package is fully compliant with european union directive 2002/95/ec. this package is nominally 4 .00mm x 4 .00 mm. the solder pads are on a 0. 5 0mm pitch. the above me chanical drawing shows the qfn - 2 0 package. all dimensions are in millimetres. the centre pad on the base of the ft231x q is internally connected to ground .
copyright ? 201 3 future technology devices international limited 39 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9.4 qfn - 20 package markings figure 9 . 4 qfn - 2 0 package markings the date code format is yyxx where xx = 2 digit week number, yy = 2 digit year number. this is followed by the revision number. the code xxxxxxx is the manufacturing lot code. ft di i xxxxxxxxxx ft231xq 6 1 yyww - b 10 15 20
copyright ? 201 3 future technology devices international limited 40 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 9.5 solder reflow profile the ft231x is supplied in pb free 20 ld ssop and qfn - 20 packages. the recommended solder reflow profile for both package options is shown in figure 9 . 5 . figure 9 . 5 ft231x solder reflow profile the recommended values for the solder reflow profile are detailed in table 9 . 1 . values are shown for both a completely pb free solder process (i.e. the ft231x is used with pb free solder), and for a non - pb free solder process (i.e. the ft231x is used with non - pb free so lder). profile feature pb free solder process non - pb free solder process average ramp up rate (t s to t p ) 3c / second max. 3c / second max. preheat - temperature min (t s min.) - temperature max (t s max.) - time (t s min to t s max) 150c 200c 60 to 12 0 seconds 100c 150c 60 to 120 seconds time maintained above critical temperature t l : - temperature (t l ) - time (t l ) 217c 60 to 150 seconds 183c 60 to 150 seconds peak temperature (t p ) 260c 240c time within 5c of actual peak temperature (t p ) 20 to 40 seconds 2 0 to 4 0 seconds ramp down rate 6c / second max. 6c / second max. time for t= 25c to peak temperature, t p 8 minutes max. 6 minutes max. table 9 . 1 reflow profile parameter values critical zone: when t is in the range t to t t e m p e r a t u r e , t ( d e g r e e s c ) time, t (seconds) 25 p t = 25 o c to t t p t p t l t preheat s t l ramp up l p ramp down t max s t min s
copyright ? 201 3 future technology devices international limited 41 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 10 contact information . head office C glasgow, uk future technology devices international limited unit 1, 2 seaward place, centurion business park glasgow g41 1hh united kingdom tel: +44 (0) 141 429 2777 fax: +44 (0) 141 429 2758 e - mail (sales) sales 1 @ftdichip.com e - mail (support) support 1 @ftdichip.com e - mail (general enquiries) admin1@ftdichip.com branch office C taipei, taiwan future technology devices international limited (taiwan) 2f, no. 516, sec. 1, neihu road taipei 114 taiwan , r.o.c. tel: +886 (0) 2 8791 3570 fax: +886 (0) 2 8791 3576 e - mail (sales) tw.sales1@ftdichip.com e - mail (support) tw.support1@ftdichip.com e - mail (general enquiries) tw.admin1@ftdichip.com branch office C tigard , oregon, usa future technology devices international limited (usa) 7130 sw fir loop tigard, or 97223 - 8160 usa tel: +1 (503) 547 0988 fax: +1 (503) 547 0987 e - mail (sales) us.sales@ftdichip.c om e - mail (support) us.support@ftdichip.com e - mail (general enquiries) us.admin@ftdichip.com branch office C shanghai, china future technology devices international limited (china) room 408, 317 xianxia road, shanghai, 200051 china tel: +86 21 62351596 fax: +86 21 62351595 e - mail (sales) cn.sales@ftdichip.com e - mail (support) cn.support@ftdichip.com e - mail (general enquiries) cn.admin@ftdichip.com web site http://ftdichip.com system and equipment manufacturers and designers are responsible to ensure that their systems, and any future technology devices international ltd (ftdi) devices incorporated in their systems, meet all applicable safety, regulatory and system - level per formance requirements. all application - related information in this document (including application descriptions, suggested ftdi devices and other materials) is provided for reference only. while ftdi has taken care to assure it is accurate, this informatio n is subject to customer confirmation, and ftdi disclaims all liability for system designs and for any applications assistance provided by ftdi. use of ftdi devices in life support and/or safety applications is entirely at the users risk, a nd the user agr ees to defend, indemnify and hold harmless ftdi from any and all damages, claims, suits or expense resulting from such use. this document is subject to change without notice. no freedom to use patents or other intellectual property rights is implied by the publication of this document. neither the whole nor any part of the information contained in, or the product described in this document, may be adapted or reproduced in any material or electronic form without the prior written consent of the copyright hol der. future technology devices international ltd, unit 1, 2 seaward place, centurion business park, glasgow g41 1hh, united kingdom. scotland registered company number: sc136640
copyright ? 201 3 future technology devices international limited 42 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 appendix a C references useful application notes http://www.ftdichip.com/documents/appnotes/an232r - 01_ ft231x bitbangmodes.pdf http://www.ftdichip.com/documents/appnotes/an_107_advanceddriveroptions_an_000073.pdf http://www.ftdichip.com/documents/appnotes/an_12 1_ftdi_device_eeprom_user_area_usage.pdf http://www.ftdichip.com/documents/appnotes/an_120_aliasing_vcp_baud_rates.pdf http://www.ftdichip.com/documents/appnotes/an_100_using_the_ft232_245r_with_external_osc(ft_ 000067).pdf http://www.ftdichip.com/resources/utilities/an_126_user_guide_for_ft232_factory%20test%20utility. pdf http://www.ftdichip.com/documents/appnotes/an232b - 05_baudrates.pdf http://www.ftdichip.com/documents/installguides.htm http://www.ftdichip.com/support/documents/technicalnotes/tn_100_usb_vid - pid_guidelines.pdf http://www.ftdichip.com/support/documents/appnotes/an_175_battery%20charging%20over%20usb %20with%20ftex%20devices.pdf http://cds.linear.com/docs/datasheet/4053 - 4.2fs.pdf http://cds.linear.com/docs/design%20note/dn320f.pdf http: //www.usb.org/developers/devclass_docs/bcv1.2_011912.zip appendix b C list of figures and tables
copyright ? 201 3 future technology devices international limited 43 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 list of figures figure 2.1 ft231x block diagram ................................ ................................ ................................ ... 4 figure 3.1 qfn schematic symbol ................................ ................................ ................................ .. 7 figure 3.2 ssop schematic symbol ................................ ................................ ................................ 9 figure 6.1 bus powered configuration ................................ ................................ ........................... 22 figure 6.2 self powered configuration ................................ ................................ ........................... 23 figure 6.3 bus powered with power switching configuration ................................ ............................ 24 figure 7.1 application example showing usb to rs232 converter ................................ ..................... 25 figure 7.2 application example showing usb to rs485 converter ................................ .................... 26 figure 7.3 usb to rs422 converter configuration ................................ ................................ ........... 27 figure 7.4 usb battery charging detection (1 pin) ................................ ................................ .......... 28 figure 7.5 usb battery charging detection (2 pin) ................................ ................................ .......... 29 figure 7.6 usb battery charging detection (3 pin) ................................ ................................ .......... 30 figure 7.7 dual led configuration ................................ ................................ ................................ 31 figure 7.8 single led configuration ................................ ................................ .............................. 31 figure 8.1: simplified memory map for the ft - x ................................ ................................ ............ 34 figure 9.1 ssop - 20 package dimensions ................................ ................................ ....................... 36 figure 9.2 ssop - 20 package markings ................................ ................................ .......................... 37 figure 9.3 qfn - 20 package dimensions ................................ ................................ ......................... 38 figure 9.4 qfn - 20 package markings ................................ ................................ ............................ 39 figure 9.5 ft231x solder reflow profile ................................ ................................ ......................... 40 list of tables table 3.1 power and ground ................................ ................................ ................................ .......... 7 table 3.2 common function pins ................................ ................................ ................................ .... 8 table 3.3 uart interface and cbus group (see note 1) ................................ ................................ .... 8 table 3.4 power and ground ................................ ................................ ................................ .......... 9 table 3.5 common function pins ................................ ................................ ................................ .... 9 table 3.6 uart interface and cbus group (see note 1) ................................ ................................ .. 10 table 3.7 cbus configuration control ................................ ................................ ........................... 12 table 5.1 absolute maximum ratings ................................ ................................ ............................ 16 table 5.2 esd and latch - up specifications ................................ ................................ .................... 16 table 5.3 operating voltage and current ................................ ................................ ....................... 17 table 5.4 i/o pin characteristics vccio = +3.3v (except usb phy pins) ................................ ........... 18 table 5.5 i/o pin characteristics vccio = +2.5v (except usb phy pins) ................................ ........... 19 table 5.6 i/o pin characteristics vccio = +1.8v (except usb phy pins) ................................ ........... 20 table 5.7 usb i/o pin (usbdp, usbdm) characteristics ................................ ................................ .. 21 table 5.8 mtp memory characteristics ................................ ................................ ........................... 21 table 5.9 internal clock characteristics ................................ ................................ ......................... 21 table 8.1 default internal mtp memory configuration ................................ ................................ ..... 33 table 9.1 reflow profile parameter values ................................ ................................ ..................... 40
copyright ? 201 3 future technology devices international limited 44 ft231x usb to full handshake uart ic datasheet version 1.2 document no.: ft_000565 clearance no.: ftdi# 261 appendix c C revision history document title: usb to full handshake uart ic ft231x document reference no.: ft_000565 clearance no.: ftdi# 261 product page: http://www.ftdichip.com/ft - x.htm document feedback: send feedback version draft initial draft available 2 nd december 2011 version 1.0 initial release 8 th february 20 12 version 1.1 added usb compliance in section 1.3 1 7 th april 2012 clarified mtp reliability in table 5.8 section 8.1, added a note vcp disabled in rev b silicon in error version 1.2 updated front page to cla r ify 5v tolerant 15 february 2013 updated tid

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