Help !! I want to interface 8051 with the 4x4 matrix keypad

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sky524810

Joined: 05 Nov 2006
Posts: 5

05 Nov 2006 9:54 Help !! I want to interface 8051 with the 4x4 matrix keypad

I want to ask how to write a program with assembly language to scans my keyboard and displays any character pressed by the user on the LCD.

For example, displays keys 0-9 as numbers 0-9 on the LCD while keys 10,11,12,13,14,15 are displayed as letters A,B,C,D,E and F, respectively.

I use uVision program.

Help!!

Thanks for reading my article!

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IanP

Joined: 05 Oct 2004
Posts: 6490
Helped: 1542
Location: West Coast

05 Nov 2006 10:16 Re: Help !! I want to interface 8051 with the 4x4 matrix key

Take a look at this example:
http://www.8052.com/codelib/4x4key%20scan
Instead of displaying the result on an LCD panel it sends it out in ASCII format through the serial port ..

Regards,
IanP

sky524810

Joined: 05 Nov 2006
Posts: 5

05 Nov 2006 10:45 Re: Help !! I want to interface 8051 with the 4x4 matrix key

thanks for your reply

I would like to ask may I use this program directly to 8051

IanP

Joined: 05 Oct 2004
Posts: 6490
Helped: 1542
Location: West Coast

05 Nov 2006 11:02 Re: Help !! I want to interface 8051 with the 4x4 matrix key

This code has been written for the AT89C2051 which is reduced-pin version of the 8051 microcontroller ..
It can be DIRECTLY use with any 8051-derivative ..
Just check Input/Output pin configuration/deffinition .. that's all ..

Inputs:

Code:

ROW0 EQU P1.0
ROW1 EQU P1.1
ROW2 EQU P1.2
ROW3 EQU P1.3

CLMN0 EQU P1.7
CLMN1 EQU P1.6
CLMN2 EQU P1.5
CLMN3 EQU P1.4

Output:

Code:

ALERT EQU P3.7 ;goes low when any key's pressed

Regards,
IanP