/* *************************************************************** *
 * Z80 LCD interface header file								   *
 * (c) 27.09.2017 Paolo Iocco									   *
 *																   *
 ***************************************************************** *
 *
 *	This code will interface to a standard LCD controller
 *	like the Hitachi HD44780. It uses it in 4 bit mode, with
 *	the hardware connected as in lcd.h
 *
 ***************************************************************** */

#include	"lcd.h"
unsigned char LCD_Port=0;


/* easy delay procedure */
void delay(int tempo){
	int i;
	for (i=0;i<=tempo;i++) {
		__asm
		nop
		__endasm;
	}
}

/* sets or clears the RS bit: CMD/DATA bit */
void lcd_rs(unsigned char command){
	if (command==DATA)
		setb(LCD_Port,RS_PIN);
	else
		clrb(LCD_Port,RS_PIN);
	//Display=LCD_Port;
}

/* generates the strobe pulse and sends the data out */
void lcd_strobe(void){
	setb(LCD_Port,EN_PIN);
	Display=LCD_Port;
	clrb(LCD_Port,EN_PIN);
	Display=LCD_Port;
}

/* write a byte to the LCD in 4 bit mode */
void lcd_write(unsigned char c) {
	LCD_Port = (LCD_Port & 0xF0) |  (c >> 4);
	lcd_strobe();
	LCD_Port = (LCD_Port & 0xF0) |  (c & 0x0F);
	lcd_strobe();
	delay(4);
}

/* Clear and home the LCD */
void lcd_clear(void) {
	lcd_rs(CMD);
	lcd_write(0x1);
	delay(200);
}

/* write a string of chars to the LCD */
void lcd_puts(const char * s) {
	while(*s)
		lcd_putch(*s++);
}

/* write one character to the LCD */
void lcd_putch(char c) {
	lcd_rs(DATA);	// write characters
	lcd_write(c);
	delay(4);
}

/* Go to the specified position */
void lcd_goto(unsigned char pos) {
	lcd_rs(CMD);
	lcd_write(0x80+pos);
}

/* initialise the LCD - put into 4 bit mode */
void lcd_init(void) {
	lcd_rs(CMD);	// write control bytes
	delay(150);	// power on delay
	LCD_Port = 0x3;	// attention!
	lcd_strobe();
	delay(500);
	lcd_strobe();
	delay(100);
	lcd_strobe();
	delay(500);
	LCD_Port = 0x2;	// set 4 bit mode
	lcd_strobe();
	delay(4);
	lcd_write(0x28);	// 4 bit mode, 1/16 duty, 5x8 font
	lcd_write(0x08);	// display off
	lcd_write(0x0F);	// display on, blink curson on
	lcd_write(0x06);	// entry mode
}