program for 4 bit lcd interface with 89s52

[Akshay]

Hii friends,

I am working on the project of DAS. In that case I designed all the circuit hardwere, but i m troubling with lcd output.

I connected the LCD in this manner using PORT 0

LCD pines : RS – P0.1 ;| R/W – P0.2 ||; EN – P0.3 ;|| DB4 – P0.4 ;|| DB5 – P0.5 ||DB6 – P0.6  ||AND||  DB7 – P0.7

Can u please help to code for this.

I found lots of codes in running mode, but anyone can't help for my case.and also tell the problem why codes are not working.

 

[Ashutosh Bhatt]

you can find many readymade codes for LCD interfacing in 4 bit mode just make change as per ur pin connections and it should work

[Anonymous]

hi akshay,

        here below you can find 4-bit lcd C prgm code.

 

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

LCD clear initialization:

 

===================

 

This is the sub-routine to initialise the lcd to 4bit. this has more advantage

 

than the 8-bit lcd. One of the advantage is using less pins compared to 8bit lcd.

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

void lcd_init() //LCD_INITIAL SUB-ROUTINE HEADER

 

{

 

cmd(0x01,0); // Lcd clear instruction

 

cmd(0x02,0);

 

cmd(0x30,0); // 8 bit initialisation

 

cmd(0x32,0); // auxillary instruction for 4 bit lcd

 

cmd(0x20,0); // 4 bit initialisation

 

cmd(0x28,0); // 4 bit, 5×7 dot matrix

 

cmd(0x0c,0); // display ON, cursor OFF

 

cmd(0x80,0); // First row, first position

 

}

 

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

4-bit lcd program sub routine:

 

=========================

 

This is the sub-routine to send data to the lcd. By seperating the 8bit data into

 

4-4bits and send to lcd using 4-lcd data lines.

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

void cmd(char p,int q) // LCD COMMAND SUB-ROUTINE HEADER

 

{

 

char r; // Declaring the character variable

 

rs=q; // selecting whether the hex is command or data

 

lcd=lcd&0xf0; // clearing the lcd's 4bit

 

r=p>>4; // source data is rotated 4 times

 

r=r&0x0f; // getting upper nibble seperately

 

lcd=lcd|r; // moving the upper nibble to lcd

 

e=1; // enabling lcd

 

delay_us(20); // delay sub-routine is called for 7u.sec

 

e=0; // disabling lcd

 

lcd=lcd&0xf0; // clearing the lcd's 4bit

 

r=p; // moving source data to 'r'

 

p=p&0x0f; // getting lower nibble seperately

 

lcd=lcd|p; // moving the lower nibble to lcd

 

e=1; // enabling lcd

 

delay_us(20); // delay sub-routine is called for 7u.sec

 

e=0; // disabling lcd

 

}

 

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

Sub-routine for to display the string in lcd :

 

===================================

 

This is the sub-routine which simplifies the string to display in the lcd and

 

make the user to prgm easier.this sub-routine includes displaying string, starting

 

address and time spend to display each character.

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

void strg_cmd(char p[],char add,int u) // STRING FUNCTION SUB-ROUTINE HEADER

 

{

 

int i,j; // Declaring the int variables

 

j=strlen(p); // measuring the string length

 

cmd(add,0); // passing the starting address to lcd

 

for(i=0;i<j;i++) // for loop continues until the last character

 

{

 

cmd(p,1); // cmd sub-routine is called

 

delay_ms(u); // delay is called for each char to display

 

}

 

}

[Anonymous]

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

HEADER FILE DECLARATION:

 

========================

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

#include<REGX52.H>;

 

#include<string.h>;

 

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

SFR AND PINS DECLARATION:

 

========================

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

sfr lcd=P0;  // 

 

sbit e=P3^6;

 

sbit rs=P3^7;

 

/*– — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —

 

SUB-ROUTINE HEADER DECLARATION:

 

===============================

 

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — */

 

void lcd_init(void);

 

void cmd(char,int);

 

void strg_cmd(char p[],char,int);

 

 

note: here R/W pin of lcd is not used, so it is not mentioned above.

 

contact: cbiinfrastructures3502gmail.com, [email protected] 

[Author]

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