Kepad lcd 8051
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The code initializes an LCD display and scans a 4x4 keypad to display the key pressed on the second line of the LCD. It sets up the LCD, displays "BOTSKOOL SHOBHIT" on the first line, and clears the second line. It then continuously scans the keypad columns, checks for pressed keys, and displays the key on the second LCD line. Functions are used to send commands/data to the LCD and add delays between steps.
Kepad lcd 8051
- 1. EN equ P2.0 RS equ P2.1 RW equ P2.2 mov A,#38H ; Setting Up the LCD lcall command mov A,#0EH ; Display On lcall command mov A,#06H ; Entry Mode lcall command mov a,#82H lcall command lcall disp ; Function Disp Called mov a,#02H ; Setting DDRAM Address to Home position lcall command lcall delay1 ; Displays BOTSKOOL SHOBHIT ON FIRST LINE OF LCD mov a,#'B' lcall datw NOP mov a,#'0' lcall datw NOP mov a,#'T' lcall datw mov a,#'S' lcall datw NOP mov a,#'K' lcall datw NOP mov a,#'0' lcall datw NOP mov a,#'0' lcall datw NOP mov a,#'L' lcall datw NOP mov a,#' ' lcall datw NOP mov a,#'S' lcall datw NOP mov a,#'H' lcall datw NOP mov a,#'O' lcall datw NOP mov a,#'B' lcall datw NOP mov a,#'H' lcall datw NOP mov a,#'I'
- 2. lcall datw NOP mov a,#'T' lcall datw MOV A,#255 ; Moving Value 255 to PORT 3 MOV P3,A ; Keypad Scan Begins sd: lcall delay1 lcall key1 lcall delay lcall key2 lcall delay lcall key3 lcall delay lcall key4 lcall delay lcall sd ; Function to Send Commands to LCD command: clr RW clr RS setB EN MOV P1,A lcall delay clr EN RET ; Function to Clear the DDRAM Content clear: mov A,#01H lcall command lcall delay mov A,#02H ; Set The DDRAM Address to Home Position lcall command lcall delay RET ; Function to Display Data on LCD Screen datw: SETB RS clr RW SETB EN MOV P1,A lcall delay clr EN RET ;Function to Display The Key Pressed datw1: lcall delay1 lcall disp lcall delay1 MOV A,R7 lcall datw RET
- 3. ; Generating Small Delay delay: mov r0,#255 loop: DJNZ r0,loop; RET ; Generating a Bigger Delay delay1: mov r1,#255 loop1: mov r3,#120 loop2: djnz r3,loop2 djnz r1,loop1 RET ; Checking for Key Press on The First Column of 4x4 Matrix KEY1: MOV A,r5 MOV r6,A clr p3.4 MOV A,p3 ANL A,#0FH MOV r2,A cjne r2,#14,n1 MOV r7,#'1' lcall datw1 lcall delay1 n1: cjne r2,#13,n2 mov r7,#'5' lcall datw1 lcall delay1 n2: cjne r2,#11,n3 mov r7,#'9' lcall datw1 lcall delay1 n3: cjne r2,#7,n4 mov r7,#'D' lcall datw1 lcall delay1 n4: lcall delay1 SETB P3.4 RET ; Checking for Key Press on the Second Column of 4x4 Matrix KEY2: clr p3.5 MOV A,p3 ANL A,#0FH MOV r2,A cjne r2,#14,q1 mov r7,#'2' lcall datw1 lcall delay1 q1: cjne r2,#13,q2 mov r7,#'6'
- 4. lcall datw1 lcall delay1 q2: cjne r2,#11,q3 mov r7,#65; A=65 lcall datw1 lcall delay1 q3: cjne r2,#7,q4 mov r7,#'E' lcall datw1 lcall delay1 q4: lcall delay SETB p3.5 RET ; Checking for Key Press On The Third Column of 4x4 Matrix KEY3: clr p3.6 MOV A,p3 ANL A,#0FH MOV r2,A cjne r2,#14,w1 mov r7,#'3' lcall datw1 lcall delay1 w1: cjne r2,#13,w2 mov r7,#'7' lcall datw1 lcall delay1 w2: cjne r2,#11,w3 mov r7,#'B' lcall datw1 lcall delay1 w3: cjne r2,#7,w4 mov r7,#'F' lcall datw1 lcall delay1 w4: lcall delay1 SETB p3.6 RET ; Checking for Key Press on the Fourth Column of 4x4 Matrix KEY4: clr p3.7 MOV A,p3 ANL A,#0FH MOV r2,A cjne r2,#14,e1 mov r7,#'4' lcall datw1 lcall delay1 e1: cjne r2,#13,e2 mov r7,#'8' lcall datw1 lcall delay1 e2: cjne r2,#11,e3 mov r7,#'C' lcall datw1
- 5. lcall delay1 e3: cjne r2,#7,e4 mov r7,#'G' lcall datw1 lcall delay1 e4: lcall delay1 SETB p3.7 RET disp: mov a,#0c0H ; Setting DDRAM Address on Second Line lcall command ; Clearing the Previous Key Pressed Information from Screen mov a,#' ' lcall datw mov a,#' ' lcall datw mov a,#' ' lcall datw mov a,#' ' lcall datw mov a,#' ' lcall datw mov a,#' ' lcall datw mov a,#0c0H ; Setting DDRAM Address on Second Line To Display “Key Pressed” lcall command ; Display "KEY" and Pressed Information mov a,#' ' lcall datw mov a,#'K' lcall datw mov a,#'E' lcall datw mov a,#'Y' lcall datw mov a,#' ' lcall datw RET END The code was written when I was learning assembly language myself and therefore the code is not optimized, but it is easy to understand if someone is willing to check the instruction set. People who want to optimize the code may wish to look into the DPTR Register and Addressing Modes Theory. A View of the Simulation