9-bit serial port with ARM Linux and FTDI UART, the desire to fix FTDI drivers

Question

I am trying to get a 9-bit serial number to communicate with a device that requires the 9th bit to receive (yes, I know ...).

I am using a fairly standard USB-RS232 dongle with an FTDI chip in it and it seems to use FTDI drivers in the system.

I used this MARK / SPACE parity guide, which, in my opinion, is the only way (?) And basing my code on this , which I believe is terrible , but, hey, I have never stopped before.

At the moment, I'm sure FTDI Linux drivers completely ignore CMSPAR, but if anyone knows otherwise, your input would be greatly appreciated. I really know that the FTDI box that I have can support a 9-bit serial number in limited capacity, because I have a key that works fine on a Windows machine .

Assuming no one has a magical answer to all of this, the main question I ask is, how difficult would it be to “fix” the FTDI driver, if necessary, to work? Also, where would it be a good place for those with limited experience with Linux device drivers? Assuming that everything is going well, it seems that I'm not the only person with this problem, so it would be great to bring something, albeit small, to the community.

Answer 1

If the ninth bit should always be high, just use 8 bits of data and another stop bit that you usually use.

For more control, use the D2XX Direct Drivers , which provide a relatively simple C API .