counter/ internal clock

[Darrel Taylor]

Here's a list of examples...

http://www.picbasic.co.uk/forum/show...2&postcount=18

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[Melanie]

> Accuracy is not very important so long as its approximatly 1sec.

Darrel - You forgot to list the obvious...

PAUSE 1000

[Darrel Taylor]

So true.

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[jimbobjones]

thanks for the replies

i cant use pause as i have other processes that need to be run..

[jimbobjones]

can anyone help with the following code as its not working

i'm trying to set the output to 100 if the timer is less than 5000 and 001 if its above....

device = 16F876a  	   			  	  	   'PIC device
CMCON = 7 								   'disable comparators
TRISB = %11111111 						   'Portb as inputs
TRISA = %00000000 						   'Porta as outputs
porta = %00000000 						   'Set all outputs low

T1CON.0=0 'stop the timer
TMR1H = 0 'Set the high part of the timer value to 0
TMR1L = 0 'Set the low part of the timer value to 0
T1CON.0=1 'start the timer

MyCount VAR WORD

Start:

MyCount.HighByte = TMR0H	'Get high byte of counter
MyCount.LowByte = TMR0L		'Get low byte of counter
 
IF MyCount > 5000 THEN 'if the timer value > than your number

porta = %00000001

gosub timer_reset

else

porta = %00000100

endif 
   
Goto Start



timer_reset:

T1CON.0=0 'stop the timer
TMR1H = 0 'Set the high part of the timer value to 0
TMR1L = 0 'Set the low part of the timer value to 0
T1CON.0=1 'start the timer

return

[mister_e]

OK, i see you have disabled the analog comparator, but not the ADCs

ADCON1=7

And... seems to miss some TIMER setting, like clock source, prescaller, Prescaller assignment.

AND, maybe i'm wrong but TIMER0 on this one is a 8 bit counter....

and have a closer look to those

MyCount.HighByte = TMR0H	'Get high byte of counter
MyCount.LowByte = TMR0L		'Get low byte of counter

maybe it's a copy/paste mistake too

[jimbobjones]

Thanks for the help

It seems I’m barking up the wrong tree then as I don't want to use an external clock source, and i can’t interrupt the program or pause it.


Is it possible simply to increment a variable every execution cycle?

i.e.

tick var byte
tick_flag var byte


start:

If tick > 99 then

Tick = 0
tick_flag = 1

Else

tick = tick + 1

End if

Goto start ‘ loop

But how can I approximate this to a time scale I can use. The datasheet state the execution cycle time as 1uS , forgive my ignorance but does that mean the above code will increment every 1uS ?