To just do a bench test of the motor drivers on the Romi bot using the power distribution board, I hooked up VREG (5V default) and GND to the power rails of a breadboard and then the SLP, DIR, and PWM pins for each motor directly to the 5V rail. The right motor works fine if I switch the three control pins back and forth between 5V and GND. However, the left motor will not change direction when I switch the DIR wire. It will coast when SLP goes low (it is pulled high on the board) and turn off when PWM is disconnected but there is not change in speed or direction if the DIR pin is on either rail or disconnected.
I noticed that the left motor driver chip is very close to the BAT2+ terminal on the distribution board. If I’m reading the specs correctly, the DVR8838 can handle only up to 260C for surface mount soldering. Is it possible while using a hand solder at above 260C that the chip could have been damaged? It is just strange that if this is the case, only the direction input was damaged?
I saw another post mention a software bug for direction control in the DRV8838 library but I’m not using any software at all. I also checked the soldering on the motor control header and it all looks good (i.e. the person soldering didn’t forget to solder that pin and it is nicely shaped like the others). I’m also confident in the jumper wire connection as I tried multiple new cables with the same results. I could try probing the traces but don’t have probes that are fine enough to just hit one pin easily and didn’t want to resort to attempting to scrape away solder mask until after asking.