Re: Configuration of the RGA200 communication baud rate

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 1/12/26 11:26 AM, Johnson, Andrew N. via Tech-talk wrote:

This blog post might be helpful on how to modify Asyn to request non-standard baud rates on some Linux systems at least.

A quick glance at "man termios" makes mention of "ioctl(TCSETS2)" in conjunction with "c_cflag |= BOTHER" (a great name!) to request arbitrary baud rates.  Might make a nice codeathon project to add this as a fallback, if only for Linux.

See EXAMPLES from:

https ://www.man7.org/linux/man-pages/man2/tcsets2.2const.html

- Andrew

-- 

Complexity comes for free, Simplicity you have to work for.

On 1/12/26, 12:26 PM, "Tech-talk" <tech-talk-bounces at aps.anl.gov> wrote:

My quick google search suggests that it’s necessary to write a program to do this.

For python it recommends:

import serial

ser = serial.Serial('/dev/ttyS0', 28800)

print(ser.baudrate)

I tried this on Debian and it ran with no complaints.

On Jan 12, 2026, at 9:53 AM, Mark Rivers <rivers at cars.uchicago.edu> wrote:

Hi Eric,

I have an RHEL 9 system.  How do I set an arbitrary baud rate using termios2 from the shell?  When I use stty I get an error:

[epics@13idd ~]$ stty -F /dev/ttyUSB0 28800

stty: invalid argument ‘28800’

Try 'stty --help' for more information.

Thanks,

Mark

— 

Eric Norum

eric at norum.ca