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: http://www.microchip.com/maps/Microcontroller.aspx 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!

PWM seriale pic 16F628

Per un progetto che vedrete prossimamente, avevo bisogno di generare un segnale PWM dalla seriale del pc... il problema principale è che mi serviva di continuare a generare lo stesso segnale anche dopo aver staccato il cavo di collegamento al pc. Bene, basta un pic, un max232 e una manciata di componenti a contorno.