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Question how to interface 8051 with the 4x4 matrix keypad

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4x4 matrix 8051

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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!
 

reading a 4x4 matrix keypad

there are two tasks
1. read the key
2. set output on LCD

first can be easily done with proper key at any of the ports and nand all of then to generate the intrrupt...

the second one can be dependent on the type of LCD you are using...
generally depending upon the datasheet provided by the manufacturer..design the easy char first and then go for custom charactors

datasheets are available on google
and all other are also depend upon the controller used...

enjoy
 

Re: Question how to interface 8051 with the 4x4 matrix keypa

Hi,

Use one uC 8-bit port and 8-bit LCD connected in 4-bit communication mode. Use 4 output lines to drive LCD bus and keyboard matrix. Read keyboard with 4 input lines. For LCD controll use to additional 2 output lines from another uC port.

This is basic idea to use same 4-bit bus for LCD and 4x4 Keyboard.
 

Re: Question how to interface 8051 with the 4x4 matrix keypa

it is easy. you can scan row or colum and remember a phenomenon "lap" or "ring" keypad. you need delay about 10ms and scan another one.
 

Re: Question how to interface 8051 with the 4x4 matrix keypa

Hi,

If you want the LCD code, you can refer this LCD 4-bits Interface to AT89C52....



Good Luck
 

see these links
**broken link removed**
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**broken link removed**

Bibin John
www.bibinjohn.tk
 

Hi refer the book,

"the 8051 and Embedded system" by Mohammed Mazdi,

You ll get all the information regarding the interface of keypad with Lcd.
Its better to use one nibble of a port to scan the Columns and another nibble to scan the row value...

regards,
Sujith
 

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