Help choosing Motor Controller

Hi guys. Let me begin by introducing a little about my project. At least the drive train. I am using a Motorola 68HC12 as my main microcontroller and have 2 planetary gear motors that are directly connected to the wheels to drive my bot. Now these are 12 V motors and I will be using a 14 V LiOn Battery and a speed controller to get the voltage back down to 12 V before making it to the motors. What I am looking for is something that will help me out with a problem.
I want to control the motor by sending outputs to the motors from the mcu. Basically 11 full forward, 10 turn left, 01, turn right, 00 full reverse. Possibly even some analog variances between 0 and 1. These motors pull 650 mA each and I was wondering what type of motorcontroller may be suitable for my application. Any help would be appreciated as well as any advice!


The Pololu dual serial motor controller ( would be a good choice. If you can program your MCU’s asynchronous serial communications interface to output eight bit numbers in four byte packets you’re set. The controller can deliver up to an amp to each motor (650 mA is your motor stall current, right?) from an input voltage of 5.6 V-25 V. You’ll be able to set each motor to 127 different speeds in each direction (plus stopped).

If you like you can use this just to drop the voltage a little and drive the motors forwards and backwards. Ideally, to deliver RMS 12 V from your 14 V battery, set your speed command number to 93 (0x5D). If your batteries actually sit a little above 14 V on a full charge you can approximate the speed command number as:
(12 V/max battery voltage)^2*127.

I have used these motor controllers in two projects, and both worked flawlessly (and withstood my misuse and abuse). The kit version requires minimal soldering, but for me was worth saving $3. The micro dual serial motor controller is also cool, but unfortunately it can’t quite handle your motor voltage.