What about detecting the / edge with the capture int,
but don't bother time check/subtract etc.
When you capture a / edge, simply load one of the timers
to 50uS (between your 2 pulse widths) and when that timer
int occurs all you need to do is check the input, which
will give 0 for 25uS pulse and 1 for a 75uS pulse.
You don't need to do any period measurement and it's
very low in cycles. ;o)
-Roman



Scott Dattalo wrote:

> My bit stream is a little different. Instead of Manchester encoding, my
> stream is On/Off encoding. Manchester is better. As I said before, the
> pulse stream is ~10kHz. The width of the pulse dictates 0's and 1's. At
> 10kHz, the pulses are coming in at a rate of 1 every 100 uS. 25uS wide
> pulses are zeroes and  75uS wide ones are ones.

> I decided to use the CCP module instead of a polling interrupt. I first
> program the CCP module to capture every rising edge. When I capture a
> rising I subtract from that the time I captured for the last rising edge.
> This gives the time between rising edges and should be about 100uS. After
> a rising edge is captured, I reprogram the CCP module to capture every
> falling edge. When I capture one I subtract from it the time of the last
> captured rising edge. This gives the pulse width.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body