>
> The PIC processor is 16c54, and for my application i use a internal
> clock. I want to put the chip to sleep and wake up in 1-2 sec.

Can't do it with any precision. The 16C5X has no interrupts and only the
watchdog timer can wake the chip. Its RC driven oscillator is subject
to temprature and manfacturing variations. In other words only a guestimate.

If you need precision sleep timing, take a look at the 16C6X series of chips.
Multiple timers, interrupts, and awake on interrupt can give you better
precision at not much more cost.

BAJ