signal integrity

[Srigopal007]

Hi, I was wondering if anyone cna help me with this piece of code that I am trying to generate, I am trying to do this in software but not getting the output that I really want. I am using the PIC16F777 as the pic of choice. and trying to generate a constant 120Hz PWM but it seems to not work. any help with this would be greatly appreciated. Thank you....

'========================'
here is the code that I have :

LOOP1:
duty = duty + 1
A = duty * 79
PortC.5 = 0
Pauseus 10033 - A
PortC.5 = 1
Pauseus A
if(duty < 127) then goto LOOP1
if(duty >= 127) then return
'======================='

[Srigopal007]

Ohh I forgot.. the code that I have above only lasts for like 1 or 2 seconds. how do I make it so that it will lasts for like 4-5 seconds. thankss

[mister_e]

PAUSEUS 10033 is an invalid task IMO

As i understand you want to generate a constant PWM and change duty while it's running?!? Like a 5 sec fade-in or fade-out ??

There's certainely more than one method to do it. Can you provide the crystal frequency you're using ???

[Srigopal007]

I am using 20 MHz ... for the crystal.


I have included
DEFINE OSC 20 on top of my code.

[Srigopal007]

the PwM should go from 0 to 100% duty with 120Hz constant frequency ... in lets say it takes 5 seconds to ramp up ...