/* PORT No. 
 *	PORTA RA0 to RA3 : LCD DB4to DB7(11~14pin)
 *	PORTA RA4 : LCD RS(4pin)
 *	PORTA RA5 : LCD EN(6pin)
*/
#include <pic16f1936.h>
//#include <stdio.h>
//#include <stdlib.h>
#include <xc.h>
//#include "lcd.h"

#define MHz 000000
#define _XTAL_FREQ 16MHz
//#define _XTAL_FREQ 20MHz
//#define _XTAL_FREQ 64MHz

//#define lcd_rs PORTAbits.RA4      // Register select pin of LCD(4pin) 動かない
//#define LCD_EN PORTAbits.RA5      // Enable pin of LCD(6pin)　動かない
#define lcd_rs LATA4	// Register select pin of LCD(4pin)
#define LCD_EN LATA5    // Enable pin of LCD(6pin)
//#define lcd_rs RA4	// Register select pin of LCD(4pin)
//#define LCD_EN RA5    // Enable pin of LCD(6pin)

/*******重要　注意点 ******/
/*  You must Adjust the LCD contrast voltage before adjust the STROBE pulse width */
//#define LCD_STROBE	(LCD_EN=1,LCD_EN=0)	// spec. min 500ns ***fix 2009/11/17 air variable
//            at 20MHz, pulse width of (LCD_EN=1,LCD_EN=0) is about 280ns
//
#define LCD_STROBEon	(LCD_EN=1)	// spec. min 500ns ***fix 2009/11/17 air variable
#define LCD_STROBEoff	(LCD_EN=0)	// spec. min 500ns ***fix 2009/11/17 air variable
/*            at 20MHz, pulse width of(LCD_EN=1;LCD_EN=0) is 280ns   */

/* write a byte to the LCD in 4 bit mode */
void
Lcd_data_byteset(unsigned char c){
    PORTA = (PORTA & 0b11110000) |  (c & 0b00001111);//set low 4bit to RA0~RA3
//    LCD_STROBE;
    LCD_EN = 1 ;
    LCD_STROBEon;
    LCD_EN = 0 ;
    LCD_STROBEoff;
}
void
Lcd_data_set(unsigned char c){
    PORTA = (PORTA & 0b11110000) | ( (c >>4) & 0b00001111 ) ;//set high 4bit to RA0~RA3
//    LCD_STROBE;
    LCD_STROBEon;
    LCD_STROBEoff;
    PORTA = (PORTA & 0b11110000) |  (c & 0b00001111 );	     //set low 4bit to RA0~RA3
//    LCD_STROBE;
    LCD_STROBEon;
    LCD_STROBEoff;
}
void
Lcd_write(unsigned char c){
    LCD_EN = 0; lcd_rs= 0;
    Lcd_data_set(c);
    __delay_us(40);
}
/* 	Clear and home the LCD */
void
Lcd_clear(void){
     LCD_EN = 0; lcd_rs = 0;
    Lcd_write(0x01);
    __delay_ms(2);
}
/* write one character to the LCD */
void
Lcd_putch(char c){
    LCD_EN = 0; lcd_rs = 1;	// write characters
    Lcd_data_set(c);
    __delay_us(40);
}
/* write a string of chars to the LCD */
void
Lcd_puts(const char * s){
    while(*s)
	Lcd_putch(*s++);
}
/* Go to the specified position */
void
Lcd_goto(unsigned char pos){
    LCD_EN = 0; lcd_rs= 0;
    Lcd_write(0x80+pos);
}
	
/* initialise the LCD - put into 4 bit mode */
void
Lcd_init(void){
    unsigned int timer_int;
    lcd_rs = 0;
    timer_int = 3; while(timer_int--){__delay_ms(10);}; //Wait 1sec.
//    __delay_ms(30);	// power on delay  min 20
    Lcd_data_byteset( 0x03 );	// attention!
//    __delay_ms(45);
    __delay_ms(5);
//    LCD_STROBE;
    LCD_STROBEon;
    LCD_STROBEoff;
    __delay_ms(1);      //better 100ms
//    LCD_STROBE;
    LCD_STROBEon;
    LCD_STROBEoff;
    __delay_ms(5);

    Lcd_data_byteset( 0x02 ) ;	// set 4 bit mode
    __delay_us(40);	//
    Lcd_write(0x28);	// Function Set : 2lines, 5x7 dots
    Lcd_write(0x08);	// Display Off
    Lcd_write(0x01);    //  Clear Display
//    __delay_ms(2);
    Lcd_write(0x06);	// Entry Mode Set
    Lcd_write(0x0F);	// Display On, blink of cursor
    __delay_ms(3);
 }