Kaya Dynamixel XC430 motors showing error on joystick app

I’ve got a new Kaya build assembled and a workstation up and running. The stereo dummy app worked, so I moved on to the joystick app and immediately encountered issues. I have modified the kaya_hardware.subgraph.json according to the XC430 + U2D2 interchangeability section.

2020-12-26 20:05:49.377 ERROR packages/dynamixel/gems/dynamixel.cpp@186: Error while reading register 23
2020-12-26 20:05:49.421 ERROR packages/dynamixel/gems/dynamixel.cpp@33: Dynamixel error (-3001): [RxPacketError] Unknown error code!

This is appearing in the logging output over and over again. In the Dynamixel Wizard I could confirm that the motors are moving so I think it’s a configuration issue. Any help would be much appreciated. I want to get this thing moving!

As far as I can tell the Registry 23 is CURRENT_SPEED.

Ok, this is what I can tell is happening so far. The error for register 23 is because it is trying to read 4 bytes from the ram table at position 128, which is the value for Present Velocity(aka CURRENT_SPEED in the kaya driver). The Dynamixel error (-3001) is COMM_RX_TIMEOUT := -3001 Status of Receive packet in the ::dynamixel::PacketHandler::getPacketHandler (https://emanual.robotis.com/docs/en/software/dynamixel/dynamixel_sdk/api_reference/cpp/cpp_packethandler/).

In the Dynamixel Wizard though I can query that location and get 0 when stationary and a value when moving the wheel, so I know it’s not the motor. I have no clue how to troubleshoot the connectivity issue though.

I finally got this working. The baudrate needed to be set for the Dynamixel driver to k57600. Once that was done the joystick app was working for me.