Timer using Picbasic Pro

[paul borgmeier]

Brutis,

Had you visioned using PBP interrupts, "Instant Interrupts," ASM interrupts, or polling for TMR1 overflows? This might help people help you.

Paul Borgmeier
Salt Lake City, Utah
USA

[Brutis]

Hi Paul,

Thanks for the reply, I'm using the timer1 module in PBP. But I cannot seem to get a 1 second timer from this. The most I can get is 5.24 ms before the interrupt flag gets set. Do you know how I can get a 1 second timer form TMR1?

Regards,

Brutis

[Melanie]

Have a look at Olympic Timer (search the forum) to give you an idea of how TMR1 could be used to increment variables to count whatever time period you require.

[Brutis]

Hi Melanie,

Thanks for the link. Did not fully understand all the code. Would you happen to know the simplist way to acheive a 1 second rate using the timer1. I'm using a 0.5 second rate now but I need more time to execute my code. 1 second would be great before the flag gets set. Any idea how to do this.

Thanks

Regards,

Brutis.

[Melanie]

Datasheet! *sigh*

Timer1 ticks every 1uS @ 4MHz.

It's 16 bits wide, therefore with a 4MHz clock will time 65.536mS between each Flag.

Using the 1:8 prescaler your maximum time is 8*65.536mS=524.288mS

So unless Microchip has shoved hardware into your PIC that mine doesn't have, the answer is NO, Timer1 will NEVER tick 1 second @ 4MHz.

You can always use a Bit Variable as a Flag... If BitFlag=0 and Timer1Flag then half a second has elapsed - so Set the BitFlag. If BitFlag=1 and Timer1Flag then one second has elapsed, so reset the BitFlag and start over for a new Second.

Homework: What has Timer2 got that Timer1 doesn't have?

[peterdeco1]

Timer2 has a prescaler and a postscaler. Am I right Melanie, am I right??

[Melanie]

Yup, you're right... Homework Part Deux: Which now means what's the maximum Time you can let Timer2 run for at 4MHz with all the prescalers and postscalers enabled?