generate a PWM from pic

[Guest]

I need help to use the PWM feature to generate 32 bits pulses, the pulse are generate by reading the a potentiometer from RA0,
all these 32 pulses are like this:

16 high pulse (40usec)-these pulses are use as a markers between data bits (always 40usec pluse)
16 low pulse (either 40usec or 80usec)-these pulse are represent valid data example =40usec is a 0, 80usec is a 1, the data will change according to the the RA0 port.


40us 40usec 80usec 40usec 80usec 40usec
----------- -------- ------- ------
|_____| |___________| |__________| etc.

Any body have a code that I can use?

I use the PIC18F877A

[PCM programmer]

If you tell us what device you're trying to control, then we can probably
help you more easily. Tell us the manufacturer and the part number.
Provide a link to the website.

When you do ASCII art, put it in a Code block. Then click the Preview
button to see what it will look like when it's posted. Make any required
changes and Preview it again until it looks correct.

[Steve H]

I think you might be able to control the PWM enough to change the PWM value on the fly between every pulse - but I think a simpler approach might be to bit bang the data out.

Have a loop that goes through the bits one at a time (shift left or shift right).
Put out the marker - 16 uS
Put out the 40 or 80 uS pulse base on a one or zero of the shifted data
Loop again

There is an app note on the Microchip website about generating high resolution PWM pulses which you might want to take a look at for the PWM solution.

HTH - Steve H.