- CIRCUIT DIAGRAM
- CODE
/*-----------------------------------------------------------------------*/
/* Project Name: LCD 8bit Custom Character Generation */
/* --------------------------------------------------------------------- */
#include <reg51.h>
#include <string.h>
/* Function declarations */
void delay(int);
void lcdinit(void);
void writecmd(int);
void writedata(char);
void writeline(char[]);
void ReturnHome(void);
void LCDBuildChar(unsigned char, unsigned char*);
/*-----------------------
Pin description
-------------------------
P2 is data bus
P3.0 is RS
P3.1 is E
-----------------------*/
// ----------------------- Define Custom Characters ----------------------- //
unsigned char Character1[8] = { 0x1c,0x16,0x1d,0x01,0x1d,0x16,0x1c,0x00 }; // Phone Up 1
unsigned char Character2[8] = { 0x07,0x0d,0x17,0x10,0x17,0x0d,0x07,0x00 }; // Phone Up 2
unsigned char Character3[8] = { 0x1f,0x1f,0x12,0x04,0x09,0x10,0x1f,0x00 }; // Phone Down 1
unsigned char Character4[8] = { 0x1f,0x1f,0x09,0x04,0x12,0x01,0x1f,0x00 }; // Phone Down 2
unsigned char Character5[8] = { 0x04,0x04,0x04,0x04,0x15,0x0e,0x04,0x00 }; // Downward Arrow
unsigned char Character6[8] = { 0x04,0x0e,0x15,0x04,0x04,0x04,0x04,0x00 }; // Upward Arrow
unsigned char Character7[8] = { 0x01,0x02,0x04,0x08,0x10,0x11,0x1f,0x00 }; // Curvy Object
unsigned char Character8[8] = { 0x00,0x1f,0x11,0x11,0x11,0x1f,0x00,0x00 }; // Square Box
/*---------------------------------------------------*/
/* Main program */
int main(void)
{
/* Make all ports zero */
lcdinit(); /* Initilize LCD */
writedata(0x00); /* Write Custom Character 1 */
writedata(0x01); /* Write Custom Character 2 */
writedata(' '); // Space
writedata(0x02); /* Write Custom Character 3 */
writedata(0x03); /* Write Custom Character 4 */
writedata(' '); // Space
writedata(0x04); /* Write Custom Character 5 */
writedata(0x05); /* Write Custom Character 6 */
writedata(' '); // Space
writedata(0x06); /* Write Custom Character 7 */
writedata(0x07); /* Write Custom Character 8 */
while(1)
{;}
}
/*---------------------------------------------------*/
/* Function definitons */
void delay(int a)
{
int i,j;
for(i=0;i<a;i++)
for(j=0;j<1275;j++); /* null statement */
}
void writedata(char t)
{
P3 |= 0x01; /* => RS = 1 */
P2 = t; /* Data transfer */
P3 |= 0x02; /* => E = 1 */
delay(150);
P3 &= 0xfd; /* => E = 0 */
delay(150);
}
void writecmd(int z)
{
P3 &= 0xfe; /* => RS = 1 */
P2 = z; /* Data transfer */
P3 |= 0x02; /* => E = 1 */
delay(150);
P3 &= 0xfd; /* => E = 0 */
delay(150);
}
void lcdinit(void)
{
/* ------------ Reset process from datasheet ----------- */
delay(100);
writecmd(0x30);
delay(100);
writecmd(0x30);
delay(100);
writecmd(0x30);
delay(100);
/* ----------------------------------------------------- */
writecmd(0x38); /* function set */
writecmd(0x0e); /* display on,cursor on*/
writecmd(0x01); /* clear display */
writecmd(0x06); /* entry mode, set increment */
/* ---------- Build Custom Characters -----------------*/
LCDBuildChar(0, Character1); /* Build Character1 at position 0 */
LCDBuildChar(1, Character2); /* Build Character2 at position 1 */
LCDBuildChar(2, Character3); /* Build Character3 at position 2 */
LCDBuildChar(3, Character4); /* Build Character4 at position 3 */
LCDBuildChar(4, Character5); /* Build Character5 at position 4 */
LCDBuildChar(5, Character6); /* Build Character6 at position 5 */
LCDBuildChar(6, Character7); /* Build Character6 at position 6 */
LCDBuildChar(7, Character8); /* Build Character6 at position 7 */
}
void ReturnHome(void) /* Return to 0 cursor location */
{
writecmd(0x02);
delay(1500);
}
void writeline(char Line[])
{
int i;
for(i=0;i<strlen(Line);i++)
{
writedata(Line[i]); /* Write Character */
}
ReturnHome(); /* Return to 0 cursor position */
}
/**********************************************************
Function Name: LCDBuildChar
Input:
loc: location where you want to store 0,1,2,....7
p: Pointer to pattern data
Usage:
LCDBuildChar(1,pattern);
********************************************************* */
void LCDBuildChar(unsigned char loc, unsigned char *p)
{
unsigned char i;
if(loc<8) //If valid address
{
writecmd(0x40+(loc*8)); //Write to CGRAM
for(i=0;i<8;i++)
writedata(p[i]); //Write the character pattern to CGRAM
}
writecmd(0x80); //shift back to DDRAM location 0
}
- OUTPUT
