Pwm 16f876a

[DynamoBen]

If I remove the defines I get the same results, which is nothing.

And yes, 16F876A for CodeDesigner Lite & ICProg.

[mister_e]

mmm how about the frequency? @20MHZ the minimum should be 'round 1.2KHZ if you're using HPWM.

[DynamoBen]

Here are the subs I'm using.

; -----[ LCD Contrast PWM ]-----------------------------------------
PWM_Contrast:
value=Contrast*40
HPwm 1,value,1000
Return

; -----[ LCD Backlight PWM ]----------------------------------------
PWM_BackLight:
value=Backlight*51
HPwm 2,value,1000
Return

[mister_e]

As i said, the minimum frequency should be 1.2Khz. 1.3KHZ work fine here. So change it to...

-----[ LCD Contrast PWM ]-----------------------------------------
PWM_Contrast:
value=Contrast*40
HPwm 1,value,1300
Return

; -----[ LCD Backlight PWM ]----------------------------------------
PWM_BackLight:
value=Backlight*51
HPwm 2,value,1300
Return

About now?

[DynamoBen]

Of course, you are correct changing to 1300 worked. Which, now that I think about it, makes sense because I was using the internal 8mHz clock on the 16F88.

Thanks for the help, its my first time with PWM. Needless to say I will remember this in the future.

I may ask Melanie to make a note about this in here FAQ.

[mister_e]

So my guess in the previous post #2 about SPBRG value was correct. You should modify it NOW!

And... the minimum frequency range is stated in the PBP manual... OUPS!

Glad to know it's working now.

Have fun!

[DynamoBen]

I did the RTFM thing and saw the chart. I just didn't make the link mentally between the chart and my code. I will in the future.

Thanks!