Lcd Interfacing To 8051

Thread Starter

Karandeep Singh

Joined Oct 30, 2007
6
hello everyone,
i have interfaced LCD (16*2) ,a 2 line lcd .iam able initialize and send data to first line but somehow not able to do the same with 2nd line can anybody explain me the way two initialize 2 nd line.iam using keil compiler and making program in c .ihave also gone through the values like 0x0c in controller to initialize 2nd line as 4th bit(db3) is used to initialize two line but unable to success for passing data to second 2nd line
secondly also tell me the way to scroll the data on lcd. as i now only can write on it
hope to get the contructive answers soon

Karandeep Singh
 

SgtWookie

Joined Jul 17, 2007
22,220
1) What is the controller used in the 16x2 LCD display?
2) Which 8051-compatible microcontroller are you using?
3) How do you have them connected together? (post your schematic)
 

hgmjr

Joined Jan 28, 2005
9,029
Take a look at the information present here. There are even a few example of routines for various micros including one for the 8051.

Hope this helps you out.

hgmjr
 

AlexR

Joined Jan 16, 2008
732
Look at the date of the thread!

Its over 2 years old.

The OP would have sorted out his problems long ago or else well and truly lost any interest he might have had in the subject by now.
 

walid el masry

Joined Mar 31, 2009
132
code i wrote for LCD 20x4 in c

Rich (BB code):
/*LCD 8 bit example
  rs => Register Select [Command : Data]
        0 => Command
        1 => Data
  rw => Read/Write [Write : Read]
        0 => Write
        1 => Read
  en => Enable signal [High to Low]
*/
#define LCD_data PORTC
//****************************************************
//    These statements doesn't apply in Mikroc
/*#define LCD_rs   PORTA.B0
#define LCD_rw   PORTA.B1
#define LCD_en   PORTA.B2
#define LCD_D7   PORTC.B7*/
//****************************************************
void LCD_busy() {
     //delay is in case you don't want to check the buzy flag
     delay_ms(1);//it is very important to return to the manual for it
     //in case of chicking the buzy flag
     /*PORTC.B7 = 1;           //Make D7th bit of LCD as i/p
     PORTA.B2 = 1;           //Make port pin as o/p
     PORTA.B0 = 0;
     PORTA.B1 = 1;
     while (PORTC.B7 = 1) {
           PORTA.B2 = 0;
           PORTA.B2 = 1;
     }*/
}
void LCD_write_command () {
     PORTA.F0   = 0;        //Selected command register
     PORTA.F1   = 0;        //We are writing in command register
     PORTA.F2   = 1;        //Enable H->L
     PORTA.F2   = 0;
     LCD_busy();          //Wait for LCD to process the command
}
void LCD_clear_display () {
     LCD_data = 0x01;     //Clear LCD
     LCD_write_command();
}
void LCD_return_homee () {
     LCD_data = 0x02;     //Return LCD to Home
     LCD_write_command();
}
void LCD_entry_mode_set (unsigned int ID,unsigned int S) {
     /*
     ID => [Decrement : Increment]
           0 => Decrement
           1 => Increment
     S  => accompanies display shift
           0 => OFF
           1 => ON
     */
     LCD_data = 0x00;
     ID = ID << 1;
     LCD_data = LCD_data + 0x04 + ID + S;
     LCD_write_command();
}
void LCD_display_control (unsigned int D,unsigned int C,unsigned int B) {
     /*
     D  => Display ON/OFF
           0 => OFF
           1 => ON
     C  => Cursor ON/OFF
           0 => OFF
           1 => ON
     B  => Blink the character at the cursor position
           0 => OFF
           1 => ON
     */
     LCD_data = 0x00;
     C = C << 1;
     D = D << 2;
     LCD_data = LCD_data + 0x08 + D + C + B;
     LCD_write_command();
}
void LCD_cursor_display_shift (unsigned int SC,unsigned int RL) {
     /*
     Moves the cursor and shifts the display without changing the DDRAM contents
     SC  => [Cursor : Display]
           0 => Cursor
           1 => Display
     RL  => [Left : Right]
           0 => Left
           1 => Right
     */
     LCD_data = 0x00;
     RL = RL << 2;
     SC = SC << 3;
     LCD_data = LCD_data + 0x10 + SC + RL;
     LCD_write_command();
}
void LCD_function_set (unsigned int DL,unsigned int N,unsigned int F) {
     /*
     DL  => Data Width [4 bit : 8 bit]
           0 => 4 bit
           1 => 8 bit
     N  => Number of lines in display[1 : 2]
           0 => 1 Line
           1 => 2 Lines
     F  => Character font[5x7 : 5x10]
           0 => 5x7
           1 => 5x10
     */
     LCD_data = 0x00;
     F = F << 2;
     N = N << 3;
     DL = DL << 4;
     LCD_data = LCD_data + 0x20 + DL + N + F;
     LCD_write_command();
}
void LCD_cgram_address (unsigned int cgadrs) {
     /*
     cgadrs => CGRAM Address Binary 6 bit
     i didn't use it yet
     */
     LCD_data = 0x00;
     LCD_data = cgadrs;
     LCD_write_command();
}
void LCD_ddram_address (unsigned int ddadrs) {
     /*
     ddadrs => DDRAM Address Binary 7 bit
               Line 1 Column 1
               Binary Address : 0B10000000
               HEX Address     : 0X80

               Line 1 Column 20
               Binary Address : 0B10001111
               HEX Address     : 0X93

               Line 2 Column 1
               Binary Address : 0B11000000
               HEX Address     : 0XC0

              Line 2 Column 20
               Binary Address : 0B11001111
               HEX Address     : 0XD3

               Line 3 Column 1
               Binary Address : 0B11000000
               HEX Address     : 0X94

              Line 3 Column 20
               Binary Address : 0B11001111
               HEX Address     : 0XA7

               Line 4 Column 1
               Binary Address : 0B11000000
               HEX Address     : 0XD4

              Line 4 Column 20
               Binary Address : 0B11001111
               HEX Address     : 0XE7
               [][][][][][][][][][][][][][][][][][][][]
               [][][][][][][][][][][][][][][][][][][][]
               [][][][][][][][][][][][][][][][][][][][]
               [][][][][][][][][][][][][][][][][][][][]
                    C1     C2     C3     C4     C5     C6      C7     C8     C9    C10     C11    C12    C13    C14   C15    C16    C17    C18     C19   C20
               L1 [0X80]-[0X81]-[0X82]-[0X83]-[0X84]-[0X85]-[0X86]-[0X87]-[0X88]-[0X89]-[0X8A]-[0X8B]-[0X8C]-[0X8D]-[0X8E]-[0X8F]-[0X90]-[0X91]-[0X92]-[0X93]
               L2 [0XC0]-[0XC1]-[0XC2]-[0XC3]-[0XC4]-[0XC5]-[0XC6]-[0XC7]-[0XC8]-[0XC9]-[0XCA]-[0XCB]-[0XCC]-[0XCD]-[0XCE]-[0XCF]-[0XD0]-[0XD1]-[0XD2]-[0XD3]
               L3 [0X94]-[0X95]-[0X96]-[0X97]-[0X98]-[0X99]-[0X9A]-[0X9B]-[0X9C]-[0X9D]-[0X9E]-[0X9F]-[0XA0]-[0XA1]-[0XA2]-[0XA3]-[0XA4]-[0XA5]-[0XA6]-[0XA7]
               L4 [0XD4]-[0XD5]-[0XD6]-[0XD7]-[0XD8]-[0XD9]-[0XDA]-[0XDB]-[0XDC]-[0XDD]-[0XDE]-[0XDF]-[0XE0]-[0XE1]-[0XE2]-[0XE3]-[0XE4]-[0XE5]-[0XE6]-[0XE7]
     */
     LCD_data = 0x00;
     LCD_data = ddadrs;
     LCD_write_command();
}
void LCD_write_data(unsigned int output) {
     LCD_data = output;     //
     PORTA.F0   = 1;        //Selected data register
     PORTA.F1   = 0;        //We are writing in data register
     PORTA.F2   = 1;        //Enable H->L
     PORTA.F2   = 0;
     LCD_busy();
}
/*void LCD_write_string(unsigned char output) {
     LCD_data = output;     //Entry mode, auto increment with no shift
     PORTA.B0   = 1;        //Selected data register
     PORTA.B1   = 0;        //We are writing in data register
     PORTA.B2   = 1;        //Enable H->L
     PORTA.B2   = 0;
     LCD_busy();
}*/
void LCD_initialize() {
     LCD_function_set (1,1,0);//Function set: 2 Line, 8-bit, 5x7 dots
     LCD_display_control (1,1,1);//Display on, Curson blinking command
     LCD_clear_display();
     LCD_entry_mode_set (1,0);//Entry mode, auto increment with no shift
     LCD_ddram_address(0X80);//Line 1 Column 1
}
void main() {

     ADCON1 = 0X06;
     TRISA = 0X00;
     TRISC = 0x00;
     LCD_initialize();
     LCD_ddram_address(0X80);
     LCD_write_data('H');
     LCD_ddram_address(0XC0);
     LCD_write_data('o');
     LCD_ddram_address(0X94);
     LCD_write_data('l');
     LCD_ddram_address(0XD4);
     LCD_write_data('a');
}
to be honest this code is working in simulation but in real world not but i think it's matter of increasing the crystal frequency and i never tested it yet


 

walid el masry

Joined Mar 31, 2009
132
and that is the equivalent in assembly for microchip mcu pic16f877

Rich (BB code):
;LCD 8 bit example
;****************************************************
;    rs => Register Select [Command : Data]
;        0 => Command
;        1 => Data
;                                                       LCD_rs   PORTA.B0
;****************************************************
;    rw => Read/Write [Write : Read]
;        0 => Write
;        1 => Read
;                                                       LCD_rw   PORTA.B1
;****************************************************
;    en => Enable signal [High to Low]
;                                                       LCD_en   PORTA.B2
;****************************************************
;                                                       LCD_D7   PORTC.B7
;****************************************************
;                                                       LCD_port PORTC
;****************************************************
    LIST P=16F877A
    #INCLUDE<P16F877A.INC>
    __CONFIG _CP_OFF&_LVP_OFF&_BODEN_OFF&_PWRTE_ON&_WDT_OFF&_XT_OSC
TIME   EQU 0X20
TIMES EQU 0X21
LCD_data EQU 0X22
    ORG 0X00
;**************************
; intialize the mcu
intialize
;**************************
;initialization for delay subrutine & interrupt
    MOVLW 0X90
    MOVWF INTCON           ;Enable External Interrupt & Enable Global Interrupt Gate
    BSF STATUS,RP0         ;goto Bank1
    MOVLW 0X47
    MOVWF OPTION_REG  ;Prescaler Rate = 1:256 for TMR0 & Intrrupt Start At Falling Edge
    BCF STATUS,RP0         ;return to Bank0
;**************************
;initialization for ports
    CLRF PORTA
    BSF STATUS,RP0
    MOVLW 0X06
    MOVWF ADCON1
    BCF STATUS,RP0
    MOVLW 0X00
    TRIS PORTA;PORTA is output
    TRIS PORTC;PORTC is output
;**************************
;initialization for LCD
    CALL DELAY
    CALL LCD_initialize
;**************************
START
    MOVLW 0X80
    CALL LCD_ddram_address
    MOVLW 'H'
    CALL LCD_write_data
    MOVLW 0XC0
    CALL LCD_ddram_address
    MOVLW 'o'
    CALL LCD_write_data
    MOVLW 0X94
    CALL LCD_ddram_address
    MOVLW 'l'
    CALL LCD_write_data
    MOVLW 0XD4
    CALL LCD_ddram_address
    MOVLW 'a'
    CALL LCD_write_data
STOP
    GOTO STOP
;**********************************************************************************
LCD_busy
;BCF PORTA,0
;BSF PORTA,1
;MOVLW B'10000000'
;TRIS PORTC
;AGAIN
;BSF PORTA,2
;BCF PORTA,2
;BTFSC PORTC,7
;GOTO AGAIN;NO
;MOVLW 0X00;YES
;TRIS PORTC
;RETURN
    ;MOVLW D'1'
    ;MOVWF TIMES
    ;CALL DELAY_TIMES
    ;CALL DELAY
    CALL DELAY
    RETURN
;**********************************************************************************
LCD_write_command
    MOVF LCD_data
    MOVWF PORTC
    BCF PORTA,0;Selected command register
    BCF PORTA,1;We are writing in data register
    BSF PORTA,2;Enable H->L
    BCF PORTA,2;
    CALL LCD_busy;
    RETURN
;**********************************************************************************
LCD_clear_display
    MOVLW 0X01
    MOVWF LCD_data;Clear LCD
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_return_home
    MOVLW 0X02
    MOVWF LCD_data;Return LCD to Home
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_entry_mode_set
;     ID => [Decrement : Increment]
;           0 => Decrement
;           1 => Increment
;     S  => accompanies display shift
;           0 => OFF
;           1 => ON
;LCD_data = B'00000+1+ID+S'
    MOVWF LCD_data
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_display_control
;     D  => Display ON/OFF
;           0 => OFF
;           1 => ON
;     C  => Cursor ON/OFF
;           0 => OFF
;           1 => ON
;     B  => Blink the character at the cursor position
;           0 => OFF
;           1 => ON
;LCD_data = B'0000+1+D+C+B'
    MOVWF LCD_data
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_cursor_display_shift
;     Moves the cursor and shifts the display without changing the DDRAM contents
;     SC  => [Cursor : Display]
;           0 => Cursor
;           1 => Display
;     RL  => [Left : Right]
;           0 => Left
;           1 => Right
;LCD_data = B'000+1+SC+RL+0+0'
    MOVWF LCD_data
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_function_set
;     DL  => Data Width [4 bit : 8 bit]
;           0 => 4 bit
;           1 => 8 bit
;     N  => Number of lines in display[1 : 2]
;           0 => 1 Line
;           1 => 2 Lines
;     F  => Character font[5x7 : 5x10]
;           0 => 5x7
;           1 => 5x10
;LCD_data = B'00+1+DL+N+F+0+0'
    MOVWF LCD_data
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_cgram_address
;     cgadrs => CGRAM Address Binary 6 bit
;     i didn't use it yet
    MOVWF LCD_data;
    CALL LCD_write_command;
    RETURN
;**********************************************************************************
LCD_ddram_address
;     ddadrs => DDRAM Address Binary 7 bit
;               Line 1 Column 1
;               Binary Address : 0B10000000
;               HEX Address     : 0X80
;
;               Line 1 Column 20
;               Binary Address : 0B10001111
;               HEX Address     : 0X93
;
;               Line 2 Column 1
;               Binary Address : 0B11000000
;               HEX Address     : 0XC0
;
;              Line 2 Column 20
;               Binary Address : 0B11001111
;               HEX Address     : 0XD3
;
;               Line 3 Column 1
;               Binary Address : 0B11000000
;               HEX Address     : 0X94
;
;              Line 3 Column 20
;               Binary Address : 0B11001111
;               HEX Address     : 0XA7
;
;               Line 4 Column 1
;               Binary Address : 0B11000000
;               HEX Address     : 0XD4
;
;              Line 4 Column 20
;               Binary Address : 0B11001111
;               HEX Address     : 0XE7
;               [][][][][][][][][][][][][][][][][][][][]
;               [][][][][][][][][][][][][][][][][][][][]
;               [][][][][][][][][][][][][][][][][][][][]
;               [][][][][][][][][][][][][][][][][][][][]
;                        C1        C2       C3       C4        C5       C6        C7       C8       C9        C10     C11      C12     C13      C14     C15      C16     C17     C18     C19     C20
;               L1 [0X80]-[0X81]-[0X82]-[0X83]-[0X84]-[0X85]-[0X86]-[0X87]-[0X88]-[0X89]-[0X8A]-[0X8B]-[0X8C]-[0X8D]-[0X8E]-[0X8F]-[0X90]-[0X91]-[0X92]-[0X93]
;               L2 [0XC0]-[0XC1]-[0XC2]-[0XC3]-[0XC4]-[0XC5]-[0XC6]-[0XC7]-[0XC8]-[0XC9]-[0XCA]-[0XCB]-[0XCC]-[0XCD]-[0XCE]-[0XCF]-[0XD0]-[0XD1]-[0XD2]-[0XD3]
;               L3 [0X94]-[0X95]-[0X96]-[0X97]-[0X98]-[0X99]-[0X9A]-[0X9B]-[0X9C]-[0X9D]-[0X9E]-[0X9F]-[0XA0]-[0XA1]-[0XA2]-[0XA3]-[0XA4]-[0XA5]-[0XA6]-[0XA7]
;               L4 [0XD4]-[0XD5]-[0XD6]-[0XD7]-[0XD8]-[0XD9]-[0XDA]-[0XDB]-[0XDC]-[0XDD]-[0XDE]-[0XDF]-[0XE0]-[0XE1]-[0XE2]-[0XE3]-[0XE4]-[0XE5]-[0XE6]-[0XE7]
    MOVWF LCD_data;
    CALL LCD_write_command;     
    RETURN
;**********************************************************************************
LCD_write_data
    MOVF LCD_data
    MOVWF PORTC
    BSF PORTA,0;Selected data register
    BCF PORTA,1;We are writing in data register
    BSF PORTA,2;Enable H->L
    BCF PORTA,2;
    CALL LCD_busy;
    RETURN
;**********************************************************************************
LCD_initialize
    ;B'00+1+DL+N+F+0+0'
    MOVLW B'00111000'
    CALL LCD_function_set ;(1,1,0);//Function set: 2 Line, 8-bit, 5x7 dots
    ;B'0000+1+D+C+B'
    MOVLW B'00001111'
    CALL LCD_display_control ;(1,1,1);//Display on, Curson blinking command
    CALL LCD_clear_display;
    CALL DELAY
    CALL DELAY
    ;B'00000+1+ID+S'
    MOVLW B'00000110'
    CALL LCD_entry_mode_set ;(1,0);//Entry mode, auto increment with no shift
    ;Line 1
    MOVLW 0X80
    CALL LCD_ddram_address;(0X80);//Line 1 Column 1
    RETURN
;**********************************************************************************
DELAY_TIMES;delay looping subrutine depend on "TIMES" value
    CALL DELAY
    DECF TIMES,1
    CLRF W
    XORWF TIMES,W
    BTFSC STATUS,Z
    GOTO DELAY_TIMES;NO loop is not finished yet
    RETURN;YES loop is finished
;**********************************************************************************
DELAY;delay 1ms subrutine
    CLRF TIME
    MOVLW 0XFE
    MOVWF TMR0
WAIT
    BTFSS INTCON,TMR0IF
    GOTO WAIT;NO
    BCF INTCON,TMR0IF;YES
    INCF TIME
    MOVLW 0X01
    XORWF TIME,W
    BTFSS STATUS,Z
    GOTO WAIT;NO
    RETURN;YES
;**********************************************************************************
DELAY_SEC;delay 1 SEC subrutine
    CLRF TIME
    MOVLW 0XF6
    MOVWF TMR0
WAIT_SEC
    BTFSS INTCON,TMR0IF
    GOTO WAIT_SEC;NO
    BCF INTCON,TMR0IF;YES
    INCF TIME
    MOVLW 0X10
    XORWF TIME,W
    BTFSS STATUS,Z
    GOTO WAIT_SEC;NO
    RETURN;YES
END
note that it is in 8-bit mode
 
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