/**
* Writes a raw instruction to the LCD.
* @param command The 4-bit instruction code.
* @param data The 8-bit paramater/data to the specified instruction.
*/
void lcd_write_command(unsigned char command, unsigned char data) {
/* Wait for the busy flag to clear */
lcd_wait_busy();
/* Set Enable low, RW low, RS high to write the instruction command */
lcd_enable_low();
lcd_rw_low();
lcd_rs_high();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
/* Instruction commands are a maximum of 4 bits long, so
* just mask off the rest. */
LCD_DATA_PORT = (command&0x0F);
lcd_enable_high();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
/* Set RW low, RW low to write the instruction data */
lcd_rw_low();
lcd_rs_low();
LCD_DATA_PORT = data;
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
lcd_strobe_enable();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
}
/**
* Strobes the Enable control line to trigger the lcd to process the
* transmitted instruction.
*/
void lcd_strobe_enable(void) {
lcd_enable_high();
__asm("nop;"); __asm("nop;"); __asm("nop;");
lcd_enable_low();
__asm("nop;"); __asm("nop;"); __asm("nop;");
}
