Micro Serial Motor Controller Burnout!

Hello all and thankyou for your patience,

I was able to get the uDSMC working for a brief time with a pic18f2455 and the the tamiya twin gearbox and motors ordered from Pololu. I have a .1f cap across the motors provided with the kit.

All was going well and I was playing with issuing commands when the chip on the “left” side of the controller (not the motor driver I assume) welted up and smoked. Guess I’ll be ordering a new controller… but any ideas as to what might have caused this? I don’t believe anything should be out of spec.


It is strange that the motor driver was not the part that broke. In general, the micro dual serial motor controller is not strong enough for the motors that come with the Tamiya gearboxes, so I recommend either putting in different motors that draw less current or going with a more powerful motor controller.

I’m only speculating about what happened to your microcontroller (the smaller chip), but the Tamiya motors are extremely noisy, so it’s possible that your microcontroller went into some latch-up state when noise caused the input voltage on an I/O line to spike outside of the valid range. You might be able to improve your results by putting a resistor (about 1k) between the motor controller inputs and your main controller, and you can also improve things by pulling the reset line high with a resistor (about 10k) and then using your microcontroller as an open drain output: make it an output and pull low to reset the device, but then just make it an input (Hi-Z) and let the pull-up resistor pull the line high.

- Jan