Quote Originally Posted by BigWumpus View Post
I would use 1 timer/ccp to generate a constant interrupt as a timebase. Inside the isr you can count in order to get your frequencies...
Problem there...is that I'm busy checking/double checking for serial comm's with the OBD. Miss one those and the whole packet is toast. With ISO9141, it takes about 200ms just to get a response from OBD...a lot of wasted time there.
The '683 idea in my last post is working rather well. I only have to get the timing right. Basically, the '683 is acting just like a blinky LED, except it's not blinking an LED. Like I said, just an over-engineered 'divide-by' chip...