//LCD functions for mega128 style LCD interface
//Roger Traylor 4.25.07

#include <avr/io.h>
#define F_CPU 16000000UL //16Mhz clock
#include <util/delay.h>
#include <string.h>

#include "lcd.h"          //function prototypes defined here

#define NUM_LCD_CHARS 16 //number of chars that the LCD has in a line

void strobe_lcd(void){
	//twiddles bit 3, PORTF creating the enable signal for the LCD
        PORTF |=  0x08;  
        PORTF &= ~0x08; 
}          
 
void clear_display(void){
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	SPDR = 0x00;    //command, not data
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x01;    //clear display command
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();   //strobe the LCD enable pin
	_delay_ms(2);   //obligatory waiting for slow LCD (1.64mS)
}         

void cursor_home(void){
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	SPDR = 0x00;    //command, not data
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x02;   // cursor go home position
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(2);   //obligatory waiting for slow LCD (1.64mS)
}         
  
void home_line2(void){
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	SPDR = 0x00;    //command, not data
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0xC0;   // cursor go home on line 2
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd(); 
	_delay_ms(2);   //obligatory waiting for slow LCD (1.64mS)
}                           
 
void fill_spaces(void){
	uint8_t count;
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	for (count=0; count<=NUM_LCD_CHARS-1; count++){
	  SPDR = 0x01; //set SR for data
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  SPDR = 0x20; 
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  strobe_lcd();
	  _delay_us(100);   //obligatory waiting for slow LCD (40uS)
	}
}  
   
void char2lcd(char a_char){
	//sends a char to the LCD
	//usage: char2lcd('H');  // send an H to the LCD
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	SPDR = 0x01;   //set SR for data xfer with LSB=1
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = a_char; //send the char to the SPI port
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();  //toggle the enable bit
	_delay_us(100);   //obligatory waiting for slow LCD (40uS)
}
  
  
void string2lcd(char *lcd_str){
	//sends a string to LCD
	uint8_t count;
	while (!(SPSR & 0x80)) {}	// Wait for any pending SPI transfers to complete
	for (count=0; count<=(strlen(lcd_str)-1); count++){
	  SPDR = 0x01; //set SR for data
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  SPDR = lcd_str[count]; 
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  strobe_lcd();
	  _delay_us(100);   //obligatory waiting for slow LCD (40uS)
	}                  
} 

void lcd_init(void){
        //initalize the LCD to receive data
	uint8_t i;
	_delay_ms(15);   
	for(i=0; i<=2; i++){ //do funky initalize sequence 3 times
	  SPDR = 0x00;
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  SPDR = 0x30;
	  while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	  strobe_lcd();
	  _delay_ms(7);
	}

	SPDR = 0x00;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x38;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(5);   

	SPDR = 0x00;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x08;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(5);

	SPDR = 0x00;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x01;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(5);   

	SPDR = 0x00;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x06;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(5);

	SPDR = 0x00;
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	SPDR = 0x0C;                    // cursor off
	while (!(SPSR & 0x80)) {}	// Wait for SPI transfer to complete
	strobe_lcd();
	_delay_ms(5);
}