Hi:

I've been lurking here for a bit and have checked the various web sites for
information but I need a little help.

I've worked with the Stamp2 and BasicX-24 but would like to convert one of my
projects to a PIC based board with the intent to actually produce a product.

What I'm doing is about as plain vanilla as you can imagine. Over a 45 minute
period, the program simply switches various I/O pins HIGH or LOW in a programmed
sequence that doesn't vary. (The pins activate/deactivate 12V light
circuits/relays through a ULN2803.)  Each circuit stays on for a set amount of
time and then turns off.  Simple timing loops are used to stretch out the
sequence to 45 minutes. All the pins end up LOW at the end.

What I want is the maximum number of I/O pins possible to drive the circuits.
The more the merrier.  What I'm unclear of is how many of the I/O pins on the
various family of chips have to get used for other overhead uses such as clock,
etc. (If any?)

In other words, the 16C5xx chips have 13 I/O pins, the 16C77x have 16, 22, and
33 I/O pins, but how many are actually available on a functioning board? The
number of useable pins is the primary thing I'm looking for.

Thanks for any help you can offer.

Mike Tennent