beagle bone serial port baud rates and setup

I need to set the beaglebone with rs485 cape to run at 250kbps 8N2. can the serial port be setup this way? where might I find a reference as to how? (for those wondering why these settings, they are used for lighting control as specified by DMX512)


Hi Eric,

I needed to get the uarts working at 250kbps for some other application, and failed to do it with custom divisors that worked nicely on FTDI serial ports. In the end I hacked it into the kernel (see attached patch for drivers/tty/serial/omap-serial.c). With the applied patch just set baud rate to 38400 and it will actually be 250000. Not the cleanest way, but does the job here :wink:



serial-kernel.patch (290 Bytes)


not sure what you mean ftdi serial ports. I’m trying to use the serial ports that are available directly on the am3359 processor.

for the internal processor ports you need the patch (or another more elegant solution) to be able to use 250kbps - I was using FTDI based USB to serial converters in other projects, with them it is a lot easier to set custom baudrates such as 250kbps.

I assume I need to bit bake Angstrom from scratch to use your patch? :frowning:

Oh well, I need to for the same reason as the original poster:

stty -F /dev/ttyO4

speed 230400 baud; line = 0;

stty -F /dev/ttyO4 250000

stty: invalid argument `250000’