FTDI - DB9-USB-D3-F - MODULE

I've used the cable versions often in many different projects, usually with Hyperterminal but sometimes with other software. What software are you using ? (Actually I've never tried looping one as you describe but I can't see why it wouldn't work.

MK

It might be a problem with dataset signals: DTR, DSR, RTS, CTS.  It may be that the PC needs to have DSR asserted to accept characters.  This is not that likely, because if DSR is off you probably wouldn't be able to transmit either.  Since you're able to transmit that also suggests there's not a problem with RTS/CTS.  Still, if there's an easy way to assert DSR and CTS I'd give it a try.  For example, you might connect DTR to DSR and RTS to CTS.  You should also be able to turn off handshaking in your terminal emulator.

Another possibility is that the Win7 terminal emulator has received some garbage characters that have put it into a funny state.  I've had good luck with putty on Win7.  I've had strange behavior with Hyperterm on Windows 2000 which required restarting the program or at least resetting the link.

Update:  Also check your parity settings.  If there's a parity mismatch your terminal emulator could be discarding input characters.

Hope this helps.

I have tried it on three various computers with various terminal programs, always the same result. I have tried to use RTS/CTS, but no progress. In datasheet is written, that this module can work without flow control (the same information is written in FT232R datasheet as well).

If I connect to PC ordinary RS232 cabel, connect Rx to Tx (to make a loop) so every sent data are immediately looped back to Rx window in terminal (without any RTS/CTS etc... signals). It seems, that I have bought corrupted modules. But It is strange, two new modules and both do not work..

Thank for your comments.

vivi wrote:

 

If I connect to PC ordinary RS232 cable, connect Rx to Tx (to make a loop) so every sent data are immediately looped back to Rx window in terminal (without any RTS/CTS etc... signals). It seems, that I have bought corrupted modules. But It is strange, two new modules and both do not work..

If I understand this correctly, you have connected a standard RS-232 cable to a PC's serial port and you can loop back RXD to TXD with no problem.  (Must be an old PC )

In this case, it could be a problem with the Windows driver.  I don't know how to fix Windows drivers problems, but this might be worth searching.  FTDI's site www.ftdichip.com might have some driver-related documents that could help.

Can you draw a little diagram of your set up - I don't understand at all where the RS232 cable comes into things.

Remember the FTDI module you have is NOT RS232 - it converts USB into logic level NRZ (or Uart type) comms. It will not work with RS232 signal levels.

There are several settings in Windows for the FTDI chip driver. Can you tell us which terminal program you are using ?

MK

Uf, it already works There are two possibilities: 1) I am stupid 2) Datasheet is "little" bit confusing. Please tell me, what is correct..

1) I have FEMALE USB bridge

2) If I connected logic analyzer to pin 3 (red circled), so I could "see" sent data from terminal.

3) I have connected red circled pins together to make a loop. If the green rectangle stands for PCB, so it seems logically to me, that FTDI bridge must be under the PCB with pins upwards on the picture. I admit, that I have not read the text under the picture. I have expected, that "UART Transceiver" is a part of MCU..

3) If I connected red circled pin together to make a loop, so nothing came back to terminal => That was my problem.. Till now..

4) I have connected green circled pins together and every sent data from terminal immediately came back..Loop works !!!

Datasheet can be found here: http://www.farnell.com/datasheets/1812681.pdf  

Can you draw a little diagram of your set up - I don't understand at all where the RS232 cable comes into things..

Just connected RS232 directly to PC (no FTDI) with connected pins 2 and 3 together (just to verify functionality terminal Hercules)..

vivi wrote:

 

Uf, it already works There are two possibilities: 1) I am stupid 2) Datasheet is "little" bit confusing. Please tell me, what is correct..

The male version is designed to replace the 9-pin male DB9 connector on a PC.  In every PC I've seen, the serial connector is male DTE (Data Terminal Equipment) so that the PC acts like a terminal.  The female version is designed to replace a female DB9 connector on a modem, also known as DCE (Data Communications Equipment).  With these connectors, you can connect a terminal (or PC) to a modem with a straight-through cable with a male connector at one end and a female connector at the other.

The DB9 pins are mirror-imaged compared to each other.  If you look at a male DB9, pins 1 and 6 are on the left.  If you look at a female DB9, holes 1 and 6 are on the right.  That way when you rotate one of the connectors to link them together, pin 1 will enter hole 1, etc.

I think your error is that the figures at the top show the pinout looking through the module with X-ray vision.  That's why the red-circled pins in the diagram match the green-circled pins in the photo.  They probably drew it this way so it matches the top side of the PC board.

Yep, it's really, really confusing.  The best way to deal with RS-232 is to get an "LED line monitor", preferably as part of a "break-out box".  That way you can plug a cable between the RS-232 port and the LED monitor and see which lines are active instantly.

It looks as if you are up and running now - great.

I used to work with an engineer who wouldn't bother to to specify RX and TX because he said that in on average least 50% of cases someone would make a mistake wiring  a socket or a lead so you wasted no more time by guessing and saved yourself the hassle of thinking.

The advantage I have had over you is that I've only used the FTDI cables which have nicely un-ambiguous colour coding.

MK