ColdFire/68K Microcontrollers and ProcessorsのトピックRe: Debouce IRQ switch on M52233Demo

Debouce IRQ switch on M52233Demo

WOLF — Thu, 21 Feb 2008 02:56:30 GMT

What is the best way to debouce the switch on the demo board in software? does anyone have code that i can throw into the interrupt routine for this IRQ?

thanks

Re: Debouce IRQ switch on M52233Demo

admin — Thu, 21 Feb 2008 03:09:37 GMT

Check the 52233 manual, if IRQ pin has Shmitt trigger. If yes, you can resolve the issure by pure hardware: insert integrating RC chain between the dry switch and the IRQ pin. For typical tiny relay with bounce time 5 ms, select Rohm*Cfarad=3*0.005s.

Re: Debouce IRQ switch on M52233Demo

RickN — Thu, 21 Feb 2008 10:46:10 GMT

Hi,

You can put a small delay loop inside the IRQ before you clear the Edge Port Flag Bit in the Edge Port Flag Register. This is not very elegant, but will get the job done.

Thanks,

Rick

ISR ()

{

volatile int idx;

for (idx=0; idx<200; idx++) // you will need to tune the exit condition, 200 is just a guess.

; // spin

do some work..

clear the Edge Port Flag Bit for the specific ISRx

}

Re: Debouce IRQ switch on M52233Demo

WOLF — Fri, 22 Feb 2008 03:37:21 GMT

Thanks for your help everyone. I will Try both a an RC delay for debouncing as well as try the delay of edge detection.

Thanks again.