MOSFET control using PWM & 16C711?

[sougata]

Hi there,

Using the HWPWM is not a big issue at all. All you have to do is set the correct registers and check for overflows through interrupt. To make your life easier there is a freeware by Doug McDonale called PIC HWPWM Calculator (I cannot remember the link now).
PBP makes your life easy and lets you concentrate on the program flow but it is always a good idea to keep yourself updated with the MPASM routines. Read your manual thoroughly.

Regards

Sougata

[NavMicroSystems]

If you have followed the hints penelopepug has given
and if you are wondering why your FET is dissipating that much heat
when using PBP's PWM instead of HPWM:
scope the output and the aswer will be on your scopes screen.

[mister_e]

I feel it's the way PBP produce the PWM. I feel they switch the pin direction from output, input and then output... i didn't check the PWM assembler source but i remember few user PMs about problem at the end of a PWM execution. With a LED(s) attach to the PWM pin(s),In some case the output state was set to high, sometimes low, sometimes XYZ=> wich looks more than a pin set to input.

Problem was fix when setting the PIN to output and LOW after the execution of PWM.

I prefer to stick with timer interrupt or HPWM(if i don't need many channels)

[NavMicroSystems]

Hi Steve,

your findings match my findings which results in: "DON'T USE PWM" (in terms of PBP's Software PWM)