I've got debounce logic in there, it works fine in polled mode. I can't seem to get the output configured pins to work when the interrupt is set even if it is only set on 4 of the pins. I'm writing a program to output to some LED's to test the theory. I may be stuck using polled mode when using a keypad, but that will complicate my code and screw up my timing. Dean --- In , Doron Fael <doronf@n...> wrote: > At 14:39 06/03/2004 +0000, you wrote: > >I've got an Axiom 256 board I'm playing with and am having a problem > >getting an interrupt to work on Port H the way I want it to. I've got > >a passive keypad hooked to it 4 pins configured as output and 4 as > >input. When a key is hit it ties one of the input and output pins > >together. If I used the polled method, turn on one output pin and > >then read it to see if any of the input pins are on, then it works > >fine. When I turn on the interrupt set all the output pins high and > >press a key, I get an interrupt as expected and when I read it I get > >the input pin high like I would expect, put when I turn around and > >poll it to see when output colunm is connected, I get nothing. Its > >like the output is turned off when you are in interrupt mode. I tried > >using polled mode when the interrupt flags are set and have no luck. > >Anyone have any experiance with this and know what my problem might > >be? > > Did you account for debouncing? > > Debouncing is an electrical phenomenon caused by mechanical switches. In > this phenomenon the voltage will alternate between the two voltages (the > old voltage and the new voltage) after pressing the keypad, which will last > for some 1mSEC - 100mSEC before stabilizing on the new voltage. > > Maybe it is possible you are suffering from such debouncing. There are > several ways to overcome the debouncing. The simplest one is to perform a > delay in software to let the inputs stabilize before reading their state. > > Hope this helps, > Doron > Nohau Corporation > HC12 In-Circuit Emulators > www.nohau.com/emul12pc.html > |