Multiple PWMs, how?

johankj

New Member

• May 9, 2008

• #1

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

Well-Known Member

• May 9, 2008

• #2

How many do you need?

 

johankj

New Member

• May 9, 2008

• #3

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

Well-Known Member

• May 9, 2008

• #4

For LEDs a simple software PWM is plenty.

 

johankj

New Member

• May 9, 2008

• #5

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

Well-Known Member

• May 9, 2008

• #6

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

 

johankj

New Member

• May 9, 2008

• #7

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

New Member

• May 9, 2008

• #8

Looks like I answered my own question...

 

blueroomelectronics

Well-Known Member

• May 9, 2008

• #9

The App notes are really handy.

 

3v0

Coop Build Coordinator

Forum Supporter

• May 9, 2008

• #10

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.