multiple interupts

iyobor · Joined: 30 Mar 2004 Posts: 7

Hello everyone
Just moved ccs from picbasic and discovered that i can't use my PCM for 18F series.
In my project i used an 18F452 which had 3 ext interupts pins RB0-RB2
Does anyone know of any 16F series or 17C that have got this feature so that i can use PCM ?

Iyobor

Haplo · Joined: 06 Sep 2003 Posts: 659 Location: Sydney, Australia

One way is to use PIC16F873/4/6/7 and use the RB0 interrupt and the two capture (CCP1 and CCP2) interrupts.

iyobor · Joined: 30 Mar 2004 Posts: 7

Thanks Ali
But that is not an option for me as i am using one of the capture (CCP2) interrupts. To measure period in my program

iyobor

Haplo · Joined: 06 Sep 2003 Posts: 659 Location: Sydney, Australia

Let's say you have three interrupt sources 1,2 and 3, and you want to interrupt on rising edge. Connect sources 1 and 2 to RB0 via an OR gate, and connect sources 2 and 3 to CCP1 via another OR gate. When you get an interrupt, in the ISR you can check the flag bit of the other interrupt. If it is also set that means source 2 has interrupted. Otherwise the source is source 1 or source 3, depending on the ISR you are in. I think this method should work.

iyobor · Joined: 30 Mar 2004 Posts: 7

Thanks Ali
It makes sense

Iyobor