Hi all,

I'm using a 128x64 Graphics LCD based on the KS0108 and KS0107 drivers.
My problem is that when writting to the LCD, the byte I send is altered by the LCD.
1 bit on 2 is not what I've sent...

To demonstrate this, I've wrote a program which counts from 0 to 127 on the P2 port.
When disconnecting the LCD, and measuring with an oscilloscope, all the bits are correct according to the counter.
When connecting the LCD, bits 0,2,4 and 8 have somme irrelevant but periodic state !!!

And idea ?

Below is that I've done for both hardware and software

The microcontroller is a 89c668
and I've wired the LCD like this :

#define LCD_DI P0_0
#define LCD_RW P0_1
#define LCD_E P0_2
#define LCD_CS1 P0_3
#define LCD_CS2 P0_4
#define LCD_RST P0_5
#define LCD_DATA P2

Here under is my LCD software :

/*-------------------------------------------------------------------------------
LCD Initialization
GLCD_LcdINIT()
-------------------------------------------------------------------------------*/
void GLCD_LcdInit(void)
{
LCD_DATA=0;
LCD_DI=0;
LCD_RW=0;
LCD_E=0;
LCD_CS1=1;
LCD_CS2=0;
LCD_RST=1;
pause();
LCD_RST=0;
pause();
LCD_RST=1;
pause();

LCD_CS1=1;
LCD_CS2=0;
GLCD_LcdInstructionWrite(0x3E); // Display OFF
GLCD_LcdInstructionWrite(0xC0);
GLCD_LcdInstructionWrite(0xB8);
GLCD_LcdInstructionWrite(0x40);
GLCD_LcdInstructionWrite(0x3F); // Display ON

LCD_CS1=0;
LCD_CS2=1;
GLCD_LcdInstructionWrite(0x3E); // Display OFF
GLCD_LcdInstructionWrite(0xC0);
GLCD_LcdInstructionWrite(0xB8);
GLCD_LcdInstructionWrite(0x40);
GLCD_LcdInstructionWrite(0x3F); // Display ON

GLCD_ClearScreen();
}

/*-------------------------------------------------------------------------------
Send datas to the LCD
LcdDataWrite (U8 u8Data)
u8Data = data to send to the LCD
-------------------------------------------------------------------------------*/
void GLCD_LcdDataWrite (U8 u8Data)
{
LCD_DI = 1; // Data mode
LCD_RW = 0; // write mode
pause();
LCD_DATA = u8Data; // outbyte

LCD_E = 1;
pause();
LCD_E = 0; // strobe
pause();

LCD_E = 1;
pause();
}

/*-------------------------------------------------------------------------------
Send instruction to the LCD
LcdDataWrite (U8 u8Instruction)
u8Instruction = Instructino to send to the LCD
-------------------------------------------------------------------------------*/
void GLCD_LcdInstructionWrite (U8 u8Instruction)
{
LCD_DI = 0; // Instruction mode
LCD_RW = 0; // Write mode
pause();
LCD_DATA = u8Instruction;

LCD_E = 1;
pause();
LCD_E = 0; // strobe
pause();
LCD_E = 1;
pause();

}

/*-------------------------------------------------------------------------------
Clear the LCD screen
GLCD_ClearScren ()
-------------------------------------------------------------------------------*/
void GLCD_ClearScreen (void)
{
U8 u8Page=0xb8;
U8 u8Colomn=0;
GLCD_LcdInstructionWrite(0x40);

for (u8Page = 0xb8; u8Page < 0xc0; u8Page++)
{
LCD_CS1=1;
LCD_CS2=0;
GLCD_LcdInstructionWrite(u8Page);
for (u8Colomn = 0; u8Colomn < 128; u8Colomn++)
{
if (u8Colomn == 64)
{
LCD_CS1=0; // switch from left to right
LCD_CS2=1;
GLCD_LcdInstructionWrite(u8Page);
}
GLCD_LcdDataWrite (0x00);
}
}
}



and following is my test software :

/*-------------------------------------------------------------------------------
LCD Initialization
GLCD_LcdINIT()
-------------------------------------------------------------------------------*/
void GLCD_LcdInit(void)
{
LCD_DATA=0;
LCD_DI=0;
LCD_RW=0;
LCD_E=0;
LCD_CS1=1;
LCD_CS2=0;
LCD_RST=1;
pause();
LCD_RST=0;
pause();
LCD_RST=1;
pause();


LCD_CS1=1;
LCD_CS2=0;
GLCD_LcdInstructionWrite(0x3E); // Display OFF
GLCD_LcdInstructionWrite(0xC0);
GLCD_LcdInstructionWrite(0xB8);
GLCD_LcdInstructionWrite(0x40);
GLCD_LcdInstructionWrite(0x3F); // Display ON

LCD_CS1=0;
LCD_CS2=1;
//GLCD_LcdInstructionWrite(0x3F); // Display ON
GLCD_LcdInstructionWrite(0xC0);
GLCD_LcdInstructionWrite(0xB8);
GLCD_LcdInstructionWrite(0x40);
GLCD_LcdInstructionWrite(0x3F); // Display ON
GLCD_ClearScreen();
}

/*-------------------------------------------------------------------------------
Send datas to the LCD
LcdDataWrite (U8 u8Data)
u8Data = data to send to the LCD
-------------------------------------------------------------------------------*/
void GLCD_LcdDataWrite (U8 u8Data)
{
//LCD_E = 0;
//pause();
LCD_DI = 1; // Data mode
LCD_RW = 0; // write mode
pause();
LCD_DATA = u8Data; // outbyte

LCD_E = 1;
pause();
LCD_E = 0; // strobe
pause();
//LCD_DI = 0; // Instruction mode
LCD_E = 1;
pause();
}

/*-------------------------------------------------------------------------------
Send instruction to the LCD
LcdDataWrite (U8 u8Instruction)
u8Instruction = Instructino to send to the LCD
-------------------------------------------------------------------------------*/
void GLCD_LcdInstructionWrite (U8 u8Instruction)
{
//LCD_E = 0;
//pause();
LCD_DI = 0; // Instruction mode
LCD_RW = 0; // Write mode
pause();
LCD_DATA = u8Instruction;

LCD_E = 1;
pause();
LCD_E = 0; // strobe
pause();
LCD_E = 1;
pause();

}

/*-------------------------------------------------------------------------------
Clear the LCD screen
GLCD_ClearScren ()
-------------------------------------------------------------------------------*/
void GLCD_ClearScreen (void)
{
U8 u8Page=0xb8;
U8 u8Colomn=0;
GLCD_LcdInstructionWrite(0x40);

for (u8Page = 0xb8; u8Page < 0xc0; u8Page++)
{
LCD_CS1=1;
LCD_CS2=0;
GLCD_LcdInstructionWrite(u8Page);
for (u8Colomn = 0; u8Colomn < 128; u8Colomn++)
{
if (u8Colomn == 64)
{
LCD_CS1=0; // switch from left to right
LCD_CS2=1;
GLCD_LcdInstructionWrite(u8Page);
}
GLCD_LcdDataWrite (0x00);
}
}

}