DT-Interrupts - Is there a clash between ExtInt and IntOnChange?

[Balachandar]

Thank you Richard, for the suggestions. I will try and implement whatever I can.

I haven't written any code in Asm so far. I guess, when it comes to using multiple interrupts, learning to code in Asm may be a necessity.

What about using a second PIC for the Elapsed Timer with a common clock? Is it worth trying?

- Bala

[richard]

i doubt its really necessary , it still leaves the issue of transferring data between chips with lots of isr's running

[Ioannis]

The tricky part as I see it, under Richard's directions, is the processing of ir in the foreground. But states will help, as long as your routines are fast enough.

Better start with one task at the time and if it works ok, add another. All together might complex things and prevent debugging.

Ioannis

[mpgmike]

Here's a crazy thought; if you have 2 interrupts doing virtually the same thing, why not do both functions with only 1 interrupt? If your 100 Hz mains interrupt is clocking the same as your Timer 1, can you put your Timer 1 code in your ExtInt interrupt?

[Ioannis]

With 100Hz, I think there is a lot of time for this. Have done much worse things in ISR!

Ioannis

[Balachandar]

With 100Hz, I think there is a lot of time for this. Have done much worse things in ISR!

Ioannis

You are right Ioannis. With 100Hz, there is a lot of time. It's all a question of what needs to be done by the ISR and how quickly it can be done.

- Bala

[Ioannis]

The ISR will be triggered by the Z.C. detector and set a flag. I do not see what else should be there.

The other stuff is not critical for being in the ISR

Ioannis

[Balachandar]

Here's a crazy thought; if you have 2 interrupts doing virtually the same thing, why not do both functions with only 1 interrupt? If your 100 Hz mains interrupt is clocking the same as your Timer 1, can you put your Timer 1 code in your ExtInt interrupt?

Your thought is not at all crazy; it's quite logical.

Both IOC Int for firing the triac and Timer1 Int for the Elapsed Timer occur 100 times per second. But I cannot use the Timer1 Int for the triac since the timing should be in sync with the zero crossings of the mains. It is possible to use the zero crossings for keeping time, but the timing accuracy may not be satisfactory.

But coming to think of it, if the timer accuracy is + or - 10% it is still good enough for me.
Thanks mpgmike. Based on your suggestion, I will try out using IOC Int for both firing the triac and the Elapsed Timer.

- Bala