Keypad data reception

We'd need more info like which processor you used,language,power supply,etc.

I've used the PIC16F84 for years as 'keyboard convertors'. Gads, showing my age....

Jay

Hi, your method should work ok, you are useing the clock edge as the interrupt souce? If you have other higher priority interrups running that coould cause a problem if they are long routines, try to shorten them.

The problem still exists after I have disabled all interrupts except the external interrupt 0. The MCU used is ATMega32. The code is modified from appnote AVR313 to GCC. The following is the code:

SIGNAL(SIG_INTERRUPT0) { static unsigned char data;//Holds the received scan code if(edge)//Routine entered at falling edge { MCUCR=2;//Set interrupt on falling edge edge=0; if(--bitcount==0)//All bits received { decode(data); bitcount=11; } } else { //Routine entered at rising edge if(bitcount2)//Bit 3 to 10 is data. Parity bit, { //start and stop bits are ignored. data>>=1; if(PIN_KEY_DATA&Bit_KEY_DATA) data|=0x80;//Store a '1' } MCUCR=3;//Set interrupt on rising edge edge=1; } }

I found the problem happens more frequently when I typed fast.

I have disabled all other interrupts and found the code runs without problem.

Thanks!

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