Problem with LCD while displaying with 4 bit data transfer with 89s52

[anboli]

i interfaced the 2*16 lcd(Winstar PC-001 94V-) with 89s52 controller,

i got the displaying output while using the 8bit data transfer between them,

but im trying to reduce to 4bit, it getting problem and displaying some different data.

I send "ABCD" to LCD but it displaying 4T$ and so on...

i attached my program here, please anyone help me to solve this problem..

**********----------------------------------------***************

#include<at89x52.h>


sbit rs = P3^6;

sbit en = P3^7;


void delay(unsigned int count)
{
int i,j;
for(i=0;i<count;i++) // 100 ====> 1.5s && 1000 ====> 15s
for(j=0;j<1275;j++);
}

void lcd_command(unsigned char comm)
{
unsigned char temp_value;
temp_value = comm;
temp_value = temp_value & 0xf0;
P0 = temp_value;
P1 = temp_value;
rs=0;
en=1;
en1=1;
// rw=0;
delay(3);
en=0;
en1=0;
delay(50);
temp_value = comm << 4;
temp_value = temp_value & 0xf0;
P0 = temp_value;
P1 = temp_value;
en=1;
en1=1;
// rs=0;
// rw=0;
delay(3);
en=0;
en1=0;
}

void lcd_data(unsigned char disp)
{
unsigned char temp_value1;
temp_value1 = disp;
temp_value1 = temp_value1 & 0xf0;
P0 = temp_value1;
P1 = temp_value1;
rs=1;
rs1=1;
en=1;
en1=1;

// rw=0;
delay(3);
en=0;
en1=0;
delay(50);
temp_value1 = disp << 4;
temp_value1 = temp_value1 & 0xf0;
P0 = temp_value1;
P1 = temp_value1;
en=1;
en1=1;
// rs=0;
// rw=0;
delay(3);
en=0;
en1=0;
}

lcd_dataa(unsigned char *disp)
{
int x;
for(x=0;disp[x]!=0;x++)
{ //lcd_command(0x07);
lcd_data(disp[x]);
//delay(20);
}
}

void lcd_ini()
{ delay(3);
lcd_command(0x30);
delay(2);
lcd_command(0x30);
delay(1);
lcd_command(0x30);
delay(1);
lcd_command(0x20);
delay(1);
lcd_command(0x06);
delay(5);
lcd_command(0x01);
delay(5);
lcd_command(0x28);
delay(5);
lcd_command(0x0e);
delay(5);
lcd_command(0xc2);
delay(5);
}

void main()
{
P0 = 0x00;
P1 = 0x00;
P3 = 0x00;

lcd_ini();
lcd_data('A');
delay(300);

P0 = 0xff;
delay(300);
P0 = 0x00;

while(1)
{
lcd_command(0x01);
delay(10);

lcd_data(0x35);
delay(100);

lcd_dataa("ABCD");
delay(1000);

}
}

***********************----------------------------------********************

 

[babar_ali]

Hi
Here is a working code that i wrote for PIC18f252. Change the pins according to you settings.

 

[pjmelect]

I don't know C but I imagine that the error is in these lines, I could not understand the logic here, to many temp_value1?

temp_value1 = disp << 4;
temp_value1 = temp_value1 & 0xf0;
P0 = temp_value1;
P1 = temp_value1;

 

[nandhu015]

Post your circuit

P0 = temp_value1;
P1 = temp_value1;

What is need to send same value to 2 ports??

 

[anboli]

thanks,
one port is interfaced with the lcd data lines and another port is interfaced with LED to check the data's whether sending correctly or not, so only,

and after the long struggle i got the output for this program.

- - - Updated - - -

thanks,
one port is interfaced with the lcd data lines and another port is interfaced with LED to check the data's whether sending correctly or not, so only,

and after the long struggle i got the output for this program.