Barry

Hello all,
How do I connect a digital pulse generator to a PIC? The PIC is programmed to count pulses before triggering an event. It is a bit tedious to sit and keep pressing a switch all the time!
The pulse generator has two outputs. The pulse generator circuit was found at http://braincambre500.freeservers.com/dpg.htm
All comments are appreciated.
Thank you in advance.
Barry.

crust

You would set the pulse generator to whatever frequency you need and the voltage to 0->Vcc. Then you can just directly connect it to your input pin, though I would suggest you connect it through a 1K resistor, just in case your PIC firmware accidentally drives the pin.

ivancho

You have 2 leads because one is ground. YOu must share ground with your PIC circuit for the Pulse generator to work with your PIC.

Good Luck

Ivancho

Barry

Thanks guys. Will try it out and report back. Must first build the pulse generator. We live and we learn!
Cheers.

ChrisBennet

You can make a pulse generator with another PIC. A PIC 12F675 for example has an internal clock so your pulse generator could be very simple - the PIC plus the previously mentioned resistor on the output pin.
How cool is that?
-Chris

Barry

Intereating idea and thanks for your input Chris. How would I be able to change the output frequency (variable)?

ChrisBennet

Without adding more components you wouldn't be able to change the frequency. The pulse generator I spoke of consists of a loop that toggles the state of a pin, calls a delay routine, and then repeats. The delay has a fixed period. (You can use different delays for "signal high" delay, and "signal low" delay to control the shape of the square wave.)

To change the delay period/count externally you could use a potentiometer and one of the pins as an A/D input to get a number you could use to calculate your delay period. Of course that would double the number of components in your circuit to 2.
-Chris

Nigel Goodwin

Now it's getting far too complicated :!:

:P