I am perhaps going at this in the wrong way. It is a watering system and=20
I need delays in the range of 10's of
minutes up to many hours. The chip is a 16F887 and for the delays I use=20
the HI-TEC C __delay_ms()  macro.
This macro can handle delays up to about 50 seconds and I use a loop=20
with it to get the necessary total delay.
I would like to be able to interrupt via RS323 and change the parameters=20
for the watering. The precision of the
timing is not important.

I am afraid that my experience with PIC is very limited and my last=20
programming in C was many years ago.

Goran

On 2012-04-21 14:28, alan.b.pearce@stfc.ac.uk wrote:
>> A better way to do that would be to have a flag (a binary semaphore in
>> concurrent processing nomenclature) which is set by the interrupt when
>> the jump should be performed. The delay loop (which is by nature
>> executing instructions continuously) can poll the flag and execute the
>> GOTO from the main code. Since testing for a flag can be done in a
>> fixed number of cycles (two for a BTFSS) the timing delay can be
>> adjusted to accommodate the extra instructions.
> I agree - in fact it sounds like the OP should be using a state machine i=
n the code where delays are being used, and look to the interrupt to notify=
 a change of state, unless the delay times out giving a different change of=
 state.
>
--=20
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