LCD 4-bit mode Data and Control on Same Port

Your code does not take care to avoid disturbing other bits when writing to the port and/or does not take care to disregard bits that it should.

Have you looked with an oscilloscope?

"and remedy if possible"

Fix the bug(s)!

the code works fine....... But if
sorry, I did not bring my crystal ball, so I can't see your code

Erik

PS if the code is not commented and indented, do not bother to post it.

//DISPLAY 1
//-------------------------------------
void lcd_send_nibble1(int8 nibble)
{ output_bit(LCD_DB4, !!(nibble & 1)); output_barf(LCD_DB5, !!(nibble & 2)); output_bit(LCD_DB6, !!(nibble & 4)); output_bit(LCD_DB7, !!(nibble & 8));

delay_cycles(1); output_high(LCD_E1); delay_us(2); output_low(LCD_E1);
}

void lcd_send_nibble2(int8 nibble)
{ output_bit(LCD_DB4, !!(nibble & 1)); output_bit(LCD_DB5, !!(nibble & 2)); output_bit(LCD_DB6, !!(nibble & 4)); output_bit(LCD_DB7, !!(nibble & 8));

delay_cycles(1); output_high(LCD_E2); delay_us(2); output_low(LCD_E2);
}

//-----------------------------------
// This is a sub-routine

int8 lcd_read_nibble(void)
{ int8 retval;
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3

retval = 0;

output_high(LCD_E1);

WHAAAAAT();

retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);

output_lowish(LCD_E1);
delay(n & 0xf);
} //----------------------------

Erik,

Please stay calm :-)

Oh what a surprise - even with that hint, it was neither commented nor indented!

Well, apart from the classic,

// This is a sub-routine

The instructions for posting source code really are quite clearly stated: www.danlhenry.com/.../keil_code.png

Don't use TAB characters, and be sure to check carefully in th Preview before you post.

#define lcd_port P3

//LCD Registers addresses
#define LCD_EN 0x80
#define LCD_RS 0x20

void delay_ms(unsigned int x)
{ unsigned int i,j; for(j=0; j<=x; j++) { for(i=0; i<=1000; i++); }
}

void lcd_reset()
{ lcd_port = 0xFF; delayms(20); lcd_port = 0x03+LCD_EN; lcd_port = 0x03; delayms(10); lcd_port = 0x03+LCD_EN; lcd_port = 0x03; delayms(1); lcd_port = 0x03+LCD_EN; lcd_port = 0x03; delayms(1); lcd_port = 0x02+LCD_EN; lcd_port = 0x02; delayms(1);
}

void lcd_init ()
{ lcd_reset(); // Call LCD reset lcd_cmd(0x28); // 4-bit mode - 2 line - 5x7 font. lcd_cmd(0x0C); // Display no cursor - no blink. lcd_cmd(0x06); // Automatic Increment - No Display shift. lcd_cmd(0x80); // Address DDRAM with 0 offset 80h. }

void lcd_cmd (char cmd)
{ lcd_port = ((cmd >> 4) & 0x0F)|LCD_EN; lcd_port = ((cmd >> 4) & 0x0F);

lcd_port = (cmd & 0x0F)|LCD_EN; lcd_port = (cmd & 0x0F);

delayus(200); delayus(200);
}

void lcd_data (unsigned char dat)
{ lcd_port = (((dat >> 4) & 0x0F)|LCD_EN|LCD_RS); lcd_port = (((dat >> 4) & 0x0F)|LCD_RS);

lcd_port = ((dat & 0x0F)|LCD_EN|LCD_RS); lcd_port = ((dat & 0x0F)|LCD_RS);

delayus(200); delayus(200);
}

Andy,

Please stay calm :-)

The instructions for posting source code really are quite clearly stated: www.danlhenry.com/.../keil_code.png
well 'stated' but not 'read' or, at least not 'followed'

I'm perfectly calm, just want the OP to get help, which requires reading and following www.danlhenry.com/.../keil_code.png

Erik

Hmmm.... if your ability to judge "working code" is as good as your ability notice illegible source code, I think that assertion must be open to considerable doubt...

Since you did not give use the pinout lets look at 1 function WITH the pre and \pre tags

void lcd_data (unsigned char dat)
{
   lcd_port = (((dat >> 4) & 0x0F)|LCD_EN|LCD_RS); // Write High Nibble
   lcd_port = (((dat >> 4) & 0x0F)|LCD_RS);

   lcd_port = ((dat & 0x0F)|LCD_EN|LCD_RS);       // Write Low Nibble
   lcd_port = ((dat & 0x0F)|LCD_RS);

   delayus(200);                                  // wait 400 uSec
   delayus(200);
}

 I ASSUME  the data is the lower nibble