Abdulla (and Aurangzeb), I'm as confused as Paul over your replies to
this. You can easily generate delays of years with any PIC. Given a crystal
oscillator, you don't even need a timer. The common method is to generate a
timer interrupt at a convenient interval and use that `tick' to increment
software counters as you described but you don't need external hardware.

   - Tom

At 07:50 AM 4/28/98 +0300, Abdulla Aldossary wrote:
>Paul B. Webster VK2BZC wrote:
>>
>> Aurangzeb Haque wrote:
>>
>> > You can implement a timer by simply writing a couple of nested
>> > counting routines, to "spend" the CPU's time.
>>
>> ...
>>
>> > You could add sufficent number of such routines to get a desired basic
>> > unit of measurement , say 1 second.  You can then multiply by nesting
>> > more routines.
>>
>> > However because of the limited resources of the PICS, please don't
>> > expect to make a timer which is able to span a large period (from
>> > seconds to hours). For that you would need to add external hardware.
>>
>>   Can you explain that please?  One singularly popular PIC application,
>> if only as an exercise since there are plenty of clock chips purpose-
>> manufactured already, is a common LED clock such as the following:
>> http://hydromail.supelec-rennes.fr/rennes/se/equipe/jweiss/pic/pic.htm
>>
>>   .. while the rather *uncommon* version is the "propellor" clock in
>> either "digital": http://www.bobblick.com/bob/projects/mclock.html or
>> "analog" http://www.geocities.com/siliconvalley/lab/3685/analog.htm
>> versions.
>>
>>   Cheers,
>>         Paul B.
>paul, i believe as c programmer you can use for next loop to count for
>one second, once its done increment the secound counter by one untill
>seconds reaches to 60, then you increment minutes counter by one untill
>minutes counter reaches 60, then increment hours counter by one untill
>hours counter reaches 12 then you can change pm or am variable or
>continue to increment hours to 24 then you reset the whole thing back to
>zero for another day.
>
>you need to have seperate pic to do this job.
>
>
>
>abdulla aldossary
>
>dossam1e@aramco.com.sa
>
>