Writing on single pixel of Graphical LCD using 8051

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I am using AT89C51 Micro-Controller to interface it with my Graphical LCD,

Writing works fine, means i had displayed the Images on Graphical LCD, but my requirement is to just high and low a single pixel on graphical lcd...

But i don't know, why it doesn't works. (I am using KS0108 Based Graphical LCD)

//Connection Diagram
sbit GLCD_RS = P1^2;
sbit GLCD_RW = P1^3;
sbit GLCD_EN = P1^4;
sbit GLCD_CS1 = P1^0;
sbit GLCD_CS2 = P1^1;
sbit GLCD_RST = P1^5; 

sfr GLCD_DATA = 0xA0;

This is my connection diagram

//These are two macros definition for setting and clearing a single bit
#define bit_set(var,bitno) ((var) |= 1<<(bitno))
#define bit_clear(var,bitno) ((var) &= ~(1<<(bitno)))

void delay_small()
{
	unsigned char counter;
	for(counter=0;counter<8;counter++);
}
void GLCD_PULSE()
{
	GLCD_EN = 1;
	delay_small();
	GLCD_EN = 0;
}

void CHIP_LEFT()
{
	GLCD_CS1 = 1;
	GLCD_CS2 = 0;
}
void CHIP_RIGHT()
{
	GLCD_CS1 = 0;
	GLCD_CS2 = 1;
}

//Write Function
void glcd0108_write(unsigned char c)
{
	GLCD_RW = 0;	//Clear for Writing the Data
	GLCD_DATA = c;
	GLCD_PULSE();
}


unsigned char glcd0108_read(bit side)
{
	unsigned char lcd_data;
	//Set GLCD Data Pins as Input Pin
	GLCD_DATA = 0xFF;

	GLCD_RW = 1;	//Set the RW pin for Reading Purpose

	GLCD_RS = 1;	//Read Datasheet for Reading Purpose RS and RW pin must be High

	CHIP_LEFT();
	//Left Side Selected By Default

	if(side == 1)
	{
		//Select Right Side
		CHIP_RIGHT();	//Right Side Selected
	}
		
	delay_small();	//Give Some Delay
	GLCD_EN = 1;	//GLCD_EN --> High
	delay_small();
	lcd_data = GLCD_DATA;	//Get the data from the GLCD Data Pins
	lcd_data = GLCD_DATA;
	GLCD_EN = 0;	//GLCD_EN --> Low

	//Reset The Chip Select Lines
	GLCD_CS1 = 1;
	GLCD_CS2 = 1;
	return lcd_data;
}

void glcd0108_pixel(unsigned char x,unsigned char y,bit color)
{
	unsigned char lcd_data;
	bit side;
	//Set Side to Chip Left First
	CHIP_LEFT();
	side = 0;	//Initially Set Side = 0
	//if the value of x exceed the 63 then select Chip Right

	if(x > 63)
	{
		x = x - 64;
		CHIP_RIGHT();
		side = 1;
		//Right Chip Selected
	}

	GLCD_RS = 0;	//Setting LCD Controller for Instruction
	//Clear the MSB part of the Instruction Code
	bit_clear(x,7);
	//Set bit 6 also the part of Instruction Code
	bit_set(x,6);
	glcd0108_write(x);	//Set the Horizontal Address
	glcd0108_write( (y/8 & 0xBF) | 0xB8);	//Set the Vertical Page Address

	GLCD_RS = 1;	//Setting LCD Controller for Data

	lcd_data = glcd0108_read(side);	//Based on the above value of side read the Graphical LCD
	//Need two reads to get data
	lcd_data = glcd0108_read(side);
	if(color == 1)
		bit_set(lcd_data, (y%8));	//Turn on the Pixel
	else
		bit_clear(lcd_data, (y%8));	//Turn off the Pixel

	GLCD_RS = 0;	//Set for Instruction
	CHIP_LEFT();
	if(side == 1)
	{
		CHIP_RIGHT();
	}
	glcd0108_write(x);
	GLCD_RS = 1;	//Set for data
	glcd0108_write(lcd_data);
}

The function glcd0108_pixel(1,1,1); will dark the pixel on 1,1 the last one specify the dark and if replaced by zero will produce white pixel..

pls have a look at my code...
and tell me what is the problem..


i am also writing my main part

void main()
{
int i;
	P3 = 0x00;
	P0 = 0x00;
	P1 = 0x00;
	P2 = 0x00;
	glcd0108_init();	
	delay_ms(1);
        glcd0108_clear();  //Clears the Display
        P3 = glcd0108_read(0);
	glcd0108_pixel(1,1,1);
	while(1);
}

 

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I have taken half of code from your site, and changed that for 8051 and it works fine..
But i want to display only a single point (.) at different points on LCD.
For that i have to read the status at that.

And a buffer is not required for this, it can be done without the buffers, Bu i am not able to do...

any suggestion...
Pls