Interupt Settings

[acestu]

Hi,

I need to change a chart after 20 mins, so I am using an interrupt with Timer0, however I can't see how I set the period in the settings window, could somebody help me please ?

Interupt1.png

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cheers
Acestu

[Creative25]

Hi,
This is what I did.
I use timer two.
Prescaler1:16
Postscaler1:5
Rollover value 32
At32MHz this gives a frequency of exactly 3125Hz

Then use I used counters to make seconds and minutes.
If it does not have to be so precise you can also use Timer0
I have atached the macro I used.
Best Regards:
Uli

[acestu]

Hi Creative,

Thanks for posting the Macro, I have imported it but I can't find it lol , where does it end up ?

cheers
Acestu

[medelec35]

Hi Stuart,
I have posted a flowchart that toggles an output every 20minutes using a 19.6609MHz xtal.
With interrupt set at 75.00Hz, this means interrupt macro is accessed 75times evey second = once every 1/75 = 13.33ms
Its always best to choose the lowest interrupt frequency that is rounded to the nearest whole number.
75.00 is perfect!

Martin

[acestu]

Hi Martin,

Thanks for the chart, I will have a look at it now

cheers
Acestu

[Creative25]

Hi Martin Thanks
I see the 19.6609MHz xtal gives some nice interrupt Frequencies and makes things easier.
I am using the Internal Oscillator at 32MHZ , the only Frequency I found that has no decimal point was 3125Hz. I realize it is slowing down the program unnecessarily.
Is there a simpler way to create a 1 Minute counter without External Oscillator, and without using such high interrupt frequency?

Best Regards:
Uli