Allowed baud rates for Pixhawk UART for serial connections

rrr6399 · May 13, 2020, 5:04pm

I noticed that u-blox is recommending setting the baud rate of the GPS connections to 460,800 to allow the moving baseline solution to work. In my case, my base RTK is on the ground/sea vehicle not on the copter so I’d like to set the baud rate to 460,800 for the telemetry connection as well. (Assume that the radio or communication path allows 460,800). 460 is not currently on the list of allowed baud rates for the serial connections outside the USB connection. Does anybody know if I can just add that to the lookup list for baud rates or are only certain rates allowed by the Pixhawk UARTs? (I’ll go ahead and make the firmware change, but didn’t want to spend time debugging if its not allowed to start with.)

ppoirier · May 15, 2020, 9:47am

Hello
460 is not on GCS list but it is in the code

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_SerialManager/AP_SerialManager.cpp#L613


case 4:    return 4800;
case 9:    return 9600;
case 19:   return 19200;
case 38:   return 38400;
case 57:   return 57600;
case 100:  return 100000;
case 111:  return 111100;
case 115:  return 115200;
case 230:  return 230400;
case 256:  return 256000;
case 460:  return 460800;
case 500:  return 500000;
case 921:  return 921600;
case 1500:  return 1500000;
}


if (rate > 2000) {
    // assume it is a direct baudrate. This allows for users to
    // set an exact baudrate as long as it is over 2000 baud
    return (uint32_t)rate;
}

Did you tried it?

rrr6399 · May 18, 2020, 4:52pm

Based on a comment from @tridge, I just specified the full baud rate of 460800. (I don’t remember if had tried 460.) I also updated the comments for the serial baud settings so that when I merge my GPS changes that they’ll be picked up eventually by the GCSes. I still had to merge in the latest Copter-4.0 changes to support 460800 for the GPS.