Can I have interupts on any pin ?

[Acetronics2]

Hi, PMC

Looks your site is down ...

Could you check the link ???

Alain

[PMController]

Its not my site. but working for me.

[Acetronics2]

The message is :

" Internet explorer can't display the page "

no connectivity problems to others sites ...

Alain

[mackrackit]

Alain,
Use Fire Fox.

[Bonxy]

Well guys

Thanks for all your help, I've found that @20mhz its probably fast enough to just poll all the pins to check if they have changed state (this may change as I add more pins to my project), as for the pull-ups, I think im going to go with external resistor packs.

I have further questions (descriptors) , but I think its best to post in another thread, so if you are bored please take a look and help if you can

Thanks again

[Mike, K8LH]

Bonxy,

I don't see your other thread but I wanted to comment that you're correct in that you should be able to poll push button switches without any problem, even at relatively slow clock speeds, since switches produce a very slow and very easy to capture signal.

If you need lots of switches (you mentioned up to 33) then you might also consider Charlieplexing or multiplexing them. That is, organize them into columns and poll one column or row of switches at a time. You could Charlieplex 30 switches using just 6 I/O pins (and 30 diodes), or 42 switches using 7 I/O pins (and 42 diodes), or you could multiplex 32, 35, or 36 switches using just 12 I/O pins in a 4x8, 5x7, or 6x6 matrix, respectively.

On the other hand if you want to put the mcu to 'sleep' while waiting for a switch press then using one I/O pin per switch with diode 'OR' wiring to an IOC pin makes perfect sense.

Good luck on your project. Regards, Mike

[Bonxy]

Hi Mike

Thanks for that info, i never heard of "Charlieplexing" before, you can learn new word every day in electronics

Ps: I put my other thread in the USB section if you fancy a crack at it!