void main (void)
{
//init LCD
LCD_init();
//set TWBR = 32 for 100kHz SCL @ 8MHz
TWI_init(32, 0);
//write 0x55 @ 513 and print return value on LCD
LCD_puthex(EE_write_byte(513, 0x55));
//send stop
TWI_stop();
LCD_wait();
LCD_putchar(' ');
//wait for the EEPROM to finish the write operation
TWI_wait(EE_ADDR);
//read the write location again and print return code on LCD
LCD_puthex(EE_read_byte(513));
LCD_wait();
LCD_putchar(' ');
//print the value read from the EEPROM on the LCD
LCD_puthex(TWDR);
TWI_stop();
//LCD should now show "0x00 0x00 0x55_"
//where the _ is the blinking cursor.
}
void LCD_command(unsigned char command){
LCD_wait(); // is it still busy?
DDRD = 0xFF; // data port as output
PORTC &= ~(1<<LCD_RS); //RS low for Command
PORTC |= (1<<LCD_E); //Enable pin high
PORTD = command; // put data on Port
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
PORTC &= ~(1<<LCD_E); //Enable Pin Low
DDRD = 0; // release bus
}
void LCD_putchar(unsigned char data){
LCD_wait(); // is it busy?
//PortA is output
DDRD = 0xFF;
//RS high for data and Enable high
PORTC |= ((1<<LCD_RS)|(1<<LCD_E));
//put data on bus
PORTD = data;
/*the number of nops required varies with your clock frequency,
Can be altered */
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
// Enable low again
PORTC &= ~(1<<LCD_E);
//release port
DDRD = 0;
}
void LCD_send_data(uint8_t data){
LCD_send_byte(data, 1);
LCD_wait();
}
void LCD_send_command(uint8_t command){
LCD_send_byte(command, 0);
LCD_wait();
}