wrote in message
ups.com...
I need to design a circuit that I can tell it to start (digitally), and
then it will tell me when 10 minutes have passed. I just need to be
pointed in the right direction. What's the difference bewteen a
timer/clock/counter. I have a good understanding of circuit theory but
does anyone know of a good IC that can be surface mounted (and is
cheap) that I shoulod use. Any help or tips are greatly appreciated

All depends on how accurate that you need to be really. A simple timer
circuit - the CMOS version of the good old 555 is quite capable of this sort
of delay - could be set up fairly precisely in monostable mode, to do 10
minutes or thereabouts, say give or take a few seconds.

If you really need an accurate 10 minutes, then you need to use a counter.
You would start with a clock generator, probably a standard watch crystal at
32.768kHz, then divide it down to get your 10 minute interval. If you don't
want to divide as far, you can start with a lower frequency, but it's
usually convenient to use a ' binary ' frequency. A 16 bit counter on the
end of a 32k clock, will get you down to a second. You then need a further
10 bits of counter and a bit of AND-ing to get you to the 10 minutes.

You could also pick a ' custom ' frequency for the clock to suit your final
time, which saves the gates at the end.

Horses for courses really

Arfa