How to setup timers to get 3 PWM-channels with 18F452?

[petu65]

I have used 2 PWM-channels earlier but cant figure how to use three PWM:s simultaneously?

This is what I have used:

setup_timer_0(T0_EXT_H_TO_L|T0_DIV_1);
setup_timer_1(T1_EXTERNAL|T1_DIV_BY_1);
setup_timer_2(T2_DIV_BY_4,199,1); //1kHz 100=50%
setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
setup_ccp1(CCP_PWM);
setup_ccp2(CCP_PWM);

Now I need 3 PWM-channels with 1kHz duty and 10 i/o-channels. Any other chip?

[Mike Walne]

[petu65]

[PCM programmer]

[John P]

You should be able to do this with a chip that has 2 hardware PWMs. Then you write software to create the third one, using timer interrupts. But I can see a fine challenge coming up, where you need to have some PWM duty cycles which are so short that you must use just a single interrupt and a delay to create the pulse, and others which are longer and need an interrupt to start the pulse, and another interrupt to end it. But I don't see any reason why this absolutely wouldn't work.

And as always with something that needs to have precise timing, if there are other elements which conflict with your interrupts, the scheme may not be workable.

[petu65]

I ordered few 16F737 chips. They have three hardware PWM outputs, I think it's easiest way to do it

Petu