EXODUS said:
Can some body please help me Im learning about the PIC 16f88a microcontroller and im trying to get a somewhat simplified answer to creating a timmer using a 20MHZ clock all of the books that I have looked at talk about the 16f84 using a 4MHz clock I feel if I can learn how to create a timmer or delay that the rest would be easy.
P.S I need a one second delay or timmer I want an led to flash at one second intervals
Why 20mhz? The 16F88 has 8 internal 1% clocks. The fastest is 8MHz. Saves you wiring a crystal if you can live with the clock drift & error.
If you're just learning PICs the 16F88 is a good choice, but can be initially difficult to setup (lots & lots of internal peripherals) but it does have the advantage of ICD2 debugger support.
A nice easy chip would be a 12F508, not much to these little 8 pin beasties. No built in debugger support (it's an option though)
Also you could use MPLAB IDE, It has a built in simulator and you can test your programs without a single piece of hardware. It's free from Microchip. Of course they're nothing like the real thing.
Aside from a ICD2 programmer / debugger (
Obvious Inchworm Plug) if you've got scads of $$$$ you could buy an MPLAB ICE (In Circuit Emulator) these things cost a few thousand dollars but nothing beats them as far as debugging goes. Extremely fast and have special bondout versions of the PIC. They usually have plug in modules for different PICs and this can get really expensive.
If you just want a 1Hz flashing LED there are some really tiny pics out there. Many have 4 or 8 MHz clocks, you can also hook a 32768Hz watch crystal to them and they use extremly little power.
As a very rough calculation PICs use 1ma per MHz, the newer nanowatt chips can use much less.
PS on the cheap you can buy flashing LEDs.
PPS it's a 16F88 (the "a" part I've yet to see)