can anybody suggest how can i interface 3×5 keypad with aat89s52 controller..
can i convert 20 key controller ic 74c923 to 15 key controller by connecting one of the x1,...x4 keys to permanently ground or vcc.
if yes wat shud i connect to that pin -vcc or gnd.?
thanks in advance...
As per my view, you don't need to connect any IC between microcontroller and keypad.
Connect the matrix keypad directly to microcontroller.
You can find a similar code here: https://www.projectsof8051.com/downloads/asmcodes/8051-matrix-keypad.html
This code is for 3x4 matrix keypad, modify it for a 3x5 keypad.
thnks for the reply..
but the keypad i've has no vcc or gnd simple switches are there....
and thats y its not detected by the controller..m using at89s52 controller
n please if possible help me thru c code..
i dont understng asm code much.i find it tough...
thanks once again.....
connect your keypad to 74923,then out put interrupt of this must be connected to micro.when you press any key micro goes to interrupt routin , then you can read output of 74923.