Timers, is this good practice

[2camjohn]

Currently my timer interrupts every 0.000512s.

But I was thinking at the end of my timer routine I could set the timer value to 6, so that it would only count 250 times before it overflows (rather than 256), giving an interrupt every 0.0005 seconds.

So, that would certainly help make my maths easier. But is it good practice? Are there any side effects I have not considered.


Any information apprecaited.

 

[Nigel Goodwin]

Currently my timer interrupts every 0.000512s.

But I was thinking at the end of my timer routine I could set the timer value to 6, so that it would only count 250 times before it overflows (rather than 256), giving an interrupt every 0.0005 seconds.

So, that would certainly help make my maths easier. But is it good practice? Are there any side effects I have not considered.

You don't say which timer you're using?, but it's common practice to do this. However, if you use a more modern timer, such as timer2, you can set it far more easily anyway (as you can preset it's trigger value). Don't mess with the ancient timer0, where you have to bodge round it!.

 

[2camjohn]

Cheers Nigel,

Yes I was using timer0.


I just read up on timer2 and it looks pretty snazzy. I will try that....



John

 

[Nigel Goodwin]

Cheers Nigel,

Yes I was using timer0.


I just read up on timer2 and it looks pretty snazzy. I will try that....

It's a LOT easier to use, and doesn't have the problems of timer0, if you just want an accurate timed interrupt it's far better.