Can I have interupts on any pin ?

[Bruce]

At Post#3, I was trying to explain the same method.

That's what reminded me I had the schematic...;o)

[Bonxy]

WoW guys & gals, im overwhelmed with the response to this, thank you all very much.
Some of your ideas I have considdered, like a diode to the B0 pin, but I dont think that would work for my app, I need to have as many pins as input as possible which i think is about 33 at most on the 18f4550 (and 2 pins could fire at the same time), I will take a closer look at some of your suggestions on my day off work, it looks like some of it involves assembler which I dont get :-(, but Im sure I will pick something out of your ideas :-), Im just wondering if just polling the pins would be fast enough @ 20mhz, I'm gonna give all your ideas a try this w/end and see what works, thx

[Bonxy]

Just an afterthought,
do all pic micro ports/pins have internal pull up resistors ?, i've been looking at the 18f4550 datasheet but cant tell ?, maybe i'm just stupid or tired lol :-)'

Thanks

[aratti]

No, internal pullups applys only to portB.

Al.

[sayzer]

No, internal pullups applys only to portB.

Al.

Some other PICs have pull-ups on PORTA, too. I was not aware of this fact until recently.
Edit: For example, 16F630.

.... (and 2 pins could fire at the same time....

What does it matter?
If one or the other interrupts, you will get into interrupt routine anyway whether two interrupts occur at the same time or not (which I think is very close to impossible !)

While you are in interrupt routine, check the status of all pins, then act based on each of their tasks.

Something like >

RB0_Int: 'we are now in interrupt routine.
A = 0
B = 0
C = 0
D = 0
..
....
.......
IF Pin1 = 0 THEN A = 1 ' Pin1 seems to be interrupted.
IF Pin2 = 0 THEN B = 3  'Ohh, Pin2 also seems to interrupted.
....
.......

[PMController]

I Found great tutorial USING THE PIC EXTERNAL INTERRUPT on all pin

www.precision.net.in/picbasic/PIC_INT.PDF

.

[Acetronics2]

Hi, PMC

Looks your site is down ...

Could you check the link ???

Alain

[PMController]

Its not my site. but working for me.