I have several SMC’s both 1st gen and 2nd gen. I have configured them using the USB port but I want to control them with a microcontroller. However, I can’t get the board to respond. I had it plugged into a UART on my beaglebone and was writing binary commands but I was unable to receive anything back. I used a logic analyzer to confirm that the binary command was transmitted to the RX pin on the SMC. I tried both querying a variable and setting the motor speed but the SMC doesn’t respond and the TX pin stays quiet. I tried the same thing with an FTDI breakout straight to the USB of my computer with the same results.
My connections are simple TX->RX, RX->TX, GND->GND. With the beaglebone I powered the board with a 7.4 volt LiPo battery on VIN with a common ground with the board. With the FTDI breakout I’m supplying power to the board by connecting the 5v USB power to the 5v BEC.
I’m certain that there is something simple that I’m missing. Is there a common mistake that I could be making?