Hi,
am kind of a newbie to microcontroller programming. Am building a line tracking robot and am having problems connecting my two 12 V motors to the Dual VNH2SP30 Motor Driver Carrier MD03A. Am using an Atmega32 microcontroller for the project. Should I connect the inputs; INA and INB to my microcontroller ports, then ensure that the PWM pins are constantly pulled HIGH (1) to ensure the outputs change as per the input and ignore the DIAG/EN pins? Please help. 
Hello,
Why don’t you want to use the PWM pins? Anyway, if you do keep PWM high, INA and INB should be all you need to connect. However, the 5V input must be connected since that powers the pull-ups on the DIAG/EN pins, which you should monitor if you aren’t getting your motors to run.
If things don’t work, you should work on getting one motor going at a time.
- Jan