sabato 23 marzo 2013

How to use 4 HARDWARE PWM on a PIC @ 50hz

simplified block diagram of PWM operation 
(from PIC 16F1509 datasheet)
Do you need to use a servomotor with a PIC (with the PWM modules integrated in it)? it could be a problem, since servomotor works around 50Hz, which is a really-slow frequency.

I'll use the PIC 16F1509, teach you the basics, so you can arrange the code to other PICs too.

My new project (lucky me) needs 4 hardware implemented PWM source, but I noticed that the pic microcontrollers usually have just 2 or 3 PWM modules. then I discovered this useful page: which allows you to perform a parametric search over the complex pic-world. I ended up with the PIC 16F1509, which seems to be perfect: USART, 4PWM, comparator, 18 I/O pins, ADCs AND software selectable frequency for the internal oscillator!