Interfacing 4×4 keypad with LCD using 8051 microcontroller

Interfacing 4×4 keypad with LCD using 8051 microcontroller is very important step to enter big project. So here I have discussed regarding Interfacing4x4 keypad with LCD using 8051 microcontroller. In my previous post, I was discussed on Interfacing LCD with 8051 microcontroller using Mikro c for 8051. Now we can see how easily we interface keypad and send the data to LCD for display using MikroC for 8051.

Project Detail:

In this project we use AT 89c51 microcontroller and interface 4×4 keypad at port 0 and LCD at port 2.

Interfacing 4x4 keypad with LCD using 8051 microcontroller

From this Proteous simulation circuit diagram we can see that four resistors R1,R2,R3,R4 are connected in P0.0,P0.1,P0.2,P0.3. These resistors are work as a pull-up resistor. Because we know for input/output operation of port0 of 8051 microcontroller need pull-up resistor. For more details regarding ports in 8051 read my previous post “Ports in 9051 microcontroller”.

Here you see the complete embedded C code written in Mikroc for 8051 about this project “Interfacing 4×4 keypad with LCD using 8051 microcontroller”

Embedded C Code
// Name : Interfacing 4×4 keypad with LCD using 8051 microcontroller

// Author : Subham Dutta
// Date : 11-08-14
// Website : www.nbcafe.in
unsigned short kp;
// Keypad module connections
char keypadPort at P0;
// End Keypad module connections// Lcd module connections
sbit LCD_RS at P2_0_bit;
sbit LCD_EN at P2_1_bit;

sbit LCD_D4 at P2_2_bit;
sbit LCD_D5 at P2_3_bit;
sbit LCD_D6 at P2_4_bit;
sbit LCD_D7 at P2_5_bit;
// End Lcd module connections

void main() {
cnt = 0; // Reset counter
Keypad_Init(); // Initialize Keypad
Lcd_Init(); // Initialize Lcd
Lcd_Cmd(_LCD_CLEAR); // Clear display
Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off

Lcd_Out(1, 1, “Key :”); // Write message text on Lcd
Lcd_Out(2, 1, “Times:”);

do {
kp = 0; // Reset key code variable

// Wait for key to be pressed and released
do
// kp = Keypad_Key_Press(); // Store key code in kp variable
kp = Keypad_Key_Click(); // Store key code in kp variable
while (!kp);
// Prepare value for output, transform key to it’s ASCII value
switch (kp) {
//case 10: kp = 42; break; // ‘*’ // Uncomment this block for keypad4x3
//case 11: kp = 48; break; // ‘0’
//case 12: kp = 35; break; // ‘#’
//default: kp += 48;

case 1: kp = 55; break; // 1 // Uncomment this block for keypad4x4
case 2: kp = 56; break; // 2
case 3: kp = 57; break; // 3
case 4: kp = 65; break; // A
case 5: kp = 52; break; // 4
case 6: kp = 53; break; // 5
case 7: kp = 54; break; // 6
case 8: kp = 66; break; // B
case 9: kp = 49; break; // 7
case 10: kp = 50; break; // 8
case 11: kp = 51; break; // 9
case 12: kp = 67; break; // C
case 13: kp = 42; break; // *
case 14: kp = 48; break; // 0
case 15: kp = 35; break; // #
case 16: kp = 68; break; // D

}

Lcd_chr(2, 10, kp); // Display counter value on Lcd
} while (1);
}