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4x4 matrix keyboard schematics

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htrs

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Please help

Hello Everyone
I am trying to interface a 4 by 4 matrix keyboard to a 8051 microcontroller. I am trying to interface it with using INTERRUPT. So i sincerely request you to give the schematic of 4 by 4 matrix keyboard. I would be connecting only 4 lines to the keyboard. one of them wold be to the interrupt.
 

gunsuresh

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Re: Please help

u can have some information here
 

eng_ahmed22

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Re: Please help

hi
i suggests the following schematic. I didn,t use it befor, but i think it will work.
during sleep or idle let all rows 1's(P2.0 to P2.3) and all columns 0's(P2.4 to P 2.7).
if no key pressed. the nand gate will out 0,
if any key pressed the nand gate output will go high, and this well make the interrupt.

hope that help u :)
Ahmed
www.i-g.org
 

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