Multiple PWMs, how?

[johankj]

I've seen various projects that have programmed a PIC to have multiple independent(maybe?) PWM outputs, even thought the chips only have one in hardware (did I see one with none?).

Does anyone know how this is done?

 

[blueroomelectronics]

How many do you need?

 

[johankj]

Erch... I dunno... At least 3 for an RGB idea I have (moodlight-thing), but the more the merrier.

BTW, that was hella-fast!

 

[blueroomelectronics]

For LEDs a simple software PWM is plenty.

 

[johankj]

Yarh, but how? Does it have nothing to do with the hardware PWM then? And doesn't it tie up all the processing time?

 

[blueroomelectronics]

It can be all interrupt driven. Lots of code samples on the net I'm sure.

 

[johankj]

AAAHH!! I find it, I find it! No worry.

There is a technical document from Microchip themselves. AN1074 - Software PWM Generation for LED Dimming and RGB Color Applications.

 

[johankj]

Looks like I answered my own question...

 

[blueroomelectronics]

The App notes are really handy.

 

[3v0]

If you want several hardware PWM's look at one of my favorites the 18F1330. It also has a PLL that works with the internal 8MHz clock that bumps it up to 32MHz.