I use ATMEL 89c51 microcontroller with keypad 4x4. My problems is that my 1st row contain 1 2 3 A it display 1 2 3 A for every row i checked the code on proteus8 its working fine and also on 8051 kit its working fine. but on my PCB its showing 1 2 3 A for every row in column wise under 1 all are 1 and under 2 all are 2 and so on. I checked the PCB by interfacing the PCB with 8051 kit's keypad and it worked and then i connected my keypad to the alternate port of 8051 kit it is working well. but when i connect my keypad directly to the PCB it shows the problem again.What is the solution for it? <\b>
I checked the PCB by interfacing the PCB with 8051 kit's keypad and it worked and then i connected my keypad to the alternate port of 8051 kit it is working well. I GUESS it is not working when you use P0.
the other ports have "weak" pullup. you - regardless of which port - need pullups on P0 mandatory, on other ports "sluggishness prevention"
Probably a compiler bug or library bug. Contact IAR support. first why a compiler bug (very unlikely), second why contact IAR support when using Keil