PWM using a 16F873

[skimask]

I'm sure there are people here that can answer the question, but many of them only check the forum every few days or weeks.

Not to mention that there are a lot of time zones and not everybody is on your sleep schedule.

But like DT said, there's a lot of people around who are good with PWM'ing 2 motors bidirectionally, which without some sort of method of counting rev's or speed, good luck trying to get the thing to run straight.

The big thing I can suggest... Get yourself 4 LEDs, wire them up in 2 pairs of opposing parallel before getting PIC driven MOSFETs connected to motors.
That way you can play with PWM (no matter what your method, software, hardware, off-chip driven, etc), watching LED brightness, and the opposing parallel pairs of LEDs will give you a visual indication of both direction and relative speed, with practically no chance of blowing up a PIC.

[Dave]

Gixxer, I built this circuit some years ago. There are 2 such circuits. Each has a pwm channel connected to the "F" terminal and a couple of direction bits associated with it. The reason for 2 direction bits? They set the output to either battery or to ground state. for braking. This circuit is used with a 16F876 which has 2 pwm circuits available. The completed circuit runs 2 motors, forward and reverse with 10 bit pwm values.

Dave Purola,
N8NTA