TISHITU- Simulation for Keypad Interface with 8051 Microcontroller for Alpha-numeric Numbers Display

Keypad is a widely used input device with lots of application in our everyday life. From a simple telephone to keyboard of a computer, ATM, electronic lock, etc., keypad is used to take input from the user for further processing. In this article we are interfacing keypad with the MCU AT89C51 and displaying the corresponding number on LCD. This module can be further used in a number of systems to interfaced keypad with microcontroller and other processors to get desired output. The program to interface keypad with controller is written in C language which is very easy to understand.
Keypad is organized as a matrix of switches in rows and column. The article uses a 4X3 matrix keypad and a 16x2 LCD for displaying the output of keypad.
The circuit diagram shows the connection of keypad with the controller. Port P2 of the microcontroller is used to send the data for displaying on the LCD. P1^1, P1^2, P1^3 pins of microcontroller is connected to RS, RW, EN pins of LCD respectively. Port P0 is used to scan input from the keypad (refer circuit diagram for connection).
The concept of interfacing keypad with the MCU is simple. Every number is assigned two unique parameters, i.e., row and column number (n(R, C) for example 6 (2, 3)). Hence every time a key is pressed the number is identified by detecting the row and column number of the key pressed.
Initially all the rows are set to zero by the controller and the columns are scanned to check if any key is pressed. In case no key is pressed the output of all the columns will be high.
Whenever a key is pressed the row and column corresponding to the key will get short, resulting in the output of the corresponding column goes to go low (since we have made all the rows zero). This gives the column number of the pressed key.
Once the column number is detected, the controller set's all the rows to high. Now one by one each row is set to zero by controller and the earlier detected column is checked if it becomes zero. The row corresponding to which the column gets zero is the row number of the digit.The above process is very fast and even if the switch is pressed for a very small duration of time the controller can detect the key which is pressed. The controller displays the number corresponding to the row and column on the LCD.

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Please watch: "Lifi Communication by Arduino UNO Download Project"
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[TarunShrivastava]

hey buddy ... i know this is good idea to make this but if u design this by yourself this make more benefit you

[TarunShrivastava]

hey buddy watch 5:30 minut of this video.... ull find. welll vss is grounded, vdd is +5 V vee is grounded by 1k of resistance ... keep watchin :)

[supermansuperman]

which software are u using to simulate function

[sravanthit]

Hi....why we have to take 128 position... of lcd plz..

[rajput]

brother can u tell me where to connect vss, vdd, and vee of 16x2 lcd
i am interfacing with 8051

[tiktokchinafunny]

how to use timer0 interrupt in PIC 16f877
in CHIP 16f877, it's does not know this code 
void timer0() interrupt 1 //timer0 interrupt to increment cursor if de
{
   c++;
   lcdcmd(128 + c);
   TR0 = 0;               //timer0 stop
}
and it's does not know variable TR0, TH, IE, TL

please help me...i use picC compiler

[younisibrahim]

hi Tarun, my problem is I coudn't find same Alpha-numeric keypad on Proteus. all I found are different, only numeric no Alpha .
plz how I can find same this one on Proteus.
note: my Proteus is version 8.
thanks.

[sravanthit]

128 position u said like starting position of LCD i did not understand that

[sravanthit]

Hi.. i feel like complicated.. can u help me to write in simple manner only to display numbers not characters

[rjaalex]

I was wondering Simulation Software. by 8051 software name?
is  nice software program.

[sravanthit]

OK.. i will try.. n thank u for the reply...

[sravanthit]

HI....
i want to write program for keypad to display 5digit number ... how can i do that can you plz.. explain me in a simple manner

[TarunShrivastava]

you can replace character by number as well ... please waatch /watch?v=CqErT3rMrOQ