FTDI FT232RL for controlling one input - Page 1
Forum section: electronics / projects

author: rakeshm55
author_rank: Regular Contributor
timestamp: March 12, 2013, 05:34:48 am
content: Hi,I am new to FTDI and am using FT232RL as USB to serial converter.I would also like to use it to control a bit . I am using the device in its default mode.I would like to control the bit ON and OFF using my PC application.The schematics of the current design is as shown below. I would like to use one of the unused pin for this function.How to do this please advice??. I do not want to reconfigure EEPROM for converting CBUS to GPIO mode. Can I use CBUS in TXDEN to control the bit.

author: David_AVD
author_rank: Super Contributor
timestamp: March 12, 2013, 06:21:53 am
content: You should be able to control RTS (or another handshaking line) in a virtual serial port pretty easily.

author: Psi
author_rank: Super Contributor
timestamp: March 12, 2013, 06:26:54 am
content: As i understand the FT232RL it behaves exactly like a full comport in its default configuration (the config it comes with from factory).So yeah, handshaking pins should work.Try google for example code (in the language your using) for setting/clearing serial handshaking pins.

author: rakeshm55
author_rank: Regular Contributor
timestamp: March 12, 2013, 06:36:46 am
content: I am already usingTXDRXDCTSDTRRTSThis is the reason why I ask for usage of unused Pin. I want to use this s/w controlled pin to de mux some of the FTDI pins. As Of now I am using a jumper to do this. I would like to replace it with a connection form FTDI o/p pin. This pin can be bit banged to set as '1' or '0' asdesired from the user controlled s/w running in the USB host.setting a CBUS to GPIO needs reprogramming of EEprom. I would like to use the default state of the device.RegardsRakesh M.

author: Psi
author_rank: Super Contributor
timestamp: March 12, 2013, 06:44:56 am
content: You don't seem to be using the pins DCD and DSR, ive never used those before myself but i would expect them to work just like RTS etc..I'm pretty sure all the CBUS pins are disabled unless you enable them using the FTDI eeprom software. (Its pretty easy to do)I'm guessing you want to avoid adding/coding a MCU.You could add a buffered shift register on the existing lines your using and clock it in software from the PC side.That would give you plenty of extra i/o.

author: rakeshm55
author_rank: Regular Contributor
timestamp: March 12, 2013, 07:18:12 am
content: DSR DCD and RI are defined as inputs in the FT232RL data sheetwww.ftdichip.com/Documents/DataSheets/ICs/DS_FT232R.pdfIn the default mode cbus0,1,2,3, have TXLED#,RXLED#,PWREN#,SLEEP#,TXDENCan I bit bang on TXDEN so thai I could latch output with high or low??

author: rakeshm55
author_rank: Regular Contributor
timestamp: March 13, 2013, 11:51:27 am
content: Hi,Even after configuring the CBUS2 bit to I/O mode i am unable to use the D2XX driver as legacy UART function is the driver in use.Any call to FT_Open(0,&fthandle) returns a Device open failure.I guess , am not be able to use CBUS bit bang function along with legacy UART function for the FTDI TXD,RXD DCD,DTR and RTS signals.How to enable both the CBUS bitbang function and legacy UART function.

author: pspgeek
author_rank: Contributor
timestamp: March 14, 2013, 02:48:22 am
content: I have also tried to use bitbang and UART but no luck. I have also tried using different versions of the drivers.

author: David_AVD
author_rank: Super Contributor
timestamp: March 14, 2013, 02:53:14 am
content: What about using the BREAK_ON and BREAK_OFF functions in the FTDI DLL ? The DMX Open interface uses that to manually control the Tx line, but not sure how precise it is.

author: rakeshm55
author_rank: Regular Contributor
timestamp: March 14, 2013, 04:36:39 am
content: Quote??How to do this?? Is there any documentation available for BREAK_ON & BREAK_OFF functions in DLL. Will this allow me to use VCP driver for UART channel and DXX2 driver for the CBUS control???Any comments are welcome

author: David_AVD
author_rank: Super Contributor
timestamp: March 14, 2013, 05:08:38 am
content: You can use the DLL for comms but not at same time as the VCP driver I'd say.