I have two TReX Jr (FW ver 1.3) motor controllers daisy chained together and connected to a Beaglbone Black (BBB) UART (TTL serial interface). The BBB Tx pin is connected to both of the TJr receive pins and the BBB Rx pin is connected to the TJr transmit pins.
One of the TJr controller IDs was changed to ‘8’ so each TJr has a unique IDs (7 & 8) and I can successfully send commands to each controller using the ‘Pololu Protocol’ (0x80, 0x07, 0x42, 0x30) to set motor1 speed on controller 7 to 0x30. So I know the connections are properly made up. The issue is when I send a command looking for a response when the controllers are daisy chained.
If I disconnect one of the TJr, from the serial chain, and send a command expecting a return the return values are received. For example…
I send 0x81, or [0x80, 0x08, 0x01] and I receive ‘TreXJr1.3’ as expected. This works for the other controller and all other commands as well. However, when I have both controllers connected on the daisy chain no return values are received from either controller.