How best to time a pin state for extended periods of time

[Charles Linquis]

The best solution to at least half of all timing problems is using a timer interrupt. I don't know why so many people avoid that technique!

If you use an interrupt, you can do all your timing in the background.

[cncmachineguy]

While I don't disagree, when the level of accuracy is as low as this app seems to be, polling the flag seems the easier to understand solution. The OP is looking for time between 0 and 30 minuites. Seems like an INT may be just a bit overkill. Granted, we have no idea what else needs to be done in the program, so an Interrupt may well be the best overall solution.

[aratti]

If Time accuracy is not an issue then a simple routine like this should solve the problem:

Counter  Var WORD

Main:

IF Pin_1 = 0 then
PAUSE 1000  ' one second delay
Counter = Counter + 1
IF Counter >1800 then Output_3 = 1
ENDIF

IF Pin_1 = 1  and Counter > 1 then
IF Counter <= 120 then Output_1 = 1
IF Counter >120 and Conter <= 1200 then Outpt_2 = 1
IF Counter >1200 then Output_3 = 1
Counter = 0
ENDIF


GOTO Main

All the time your Pin_1 will go to zero the time check will be activated.

Cheers

Al.

[cncmachineguy]

another option with more time to do other things:

counter var word
counting var bit

turn on 16 bit timer ' @4mHz osc, this will take .065535 seconds to roll over

counter = 0

MAIN:
 IF TxIF = 1 THEN GOSUB TIMESTUFF ' TxIF is the timer interrupt flag
 
 'USER CODE GOES HERE

GOTO MAIN

TIMESTUFF:
TxIF = 0 'clear interrupt flag
 IF PIN_1 = 0 THEN 
   COUNTER = COUNTER + 1
   COUNTING = 1
 ENDIF
 IF (COUNTING) AND (PIN_1) THEN
   IF COUNTER <= 1830 THEN OUTPUT_1 = 1 ' 1 second = aproxx 15.25 counts
   IF COUNTER >1830 AND COUNTER <18300 THEN OUTPUT_2 = 1
   ' if you want to do anything for time between 20 and 30 mins, here's a good spot for that
   IF COUNTER >27450 THEN OUTPUT_3 = 1
   COUNTER = 0
   COUNTING = 0
 ENDIF
RETURN

Nothing wrong with Aratti's example, just showing another way.