/******************************************************************************
PROJECT: LCD che do 4 bit - EasyPIC
PROGRAMMER: Pham Thai Hoa (phamthaihoa@gmail.com)
MCU: PIC16F877A - 20Mhz
COMPLIER: HTPICC 8.05PL2
DES: Hien thi tren LCD 1602 dung che do 4 bit 
/*****************************************************************************/
#include <pic.h>
#include <htc.h>
#include <string.h>
#include <stdio.h>

__CONFIG(UNPROTECT & WDTEN & HS & PWRTEN & BOREN & LVPDIS & DUNPROT & DEBUGDIS);

//---------------------------------------------------------------------------//
#define		LED_ALAM		RB3
#define		LCD_EN			RB2		
#define		LCD_RW			RB1		
#define		LCD_RS			RB0	
#define		TRIS_LCD		TRISB
#define		LCD_PORT		PORTB
#define		DELAY_STROBE	200			//nebo 500
#define		LCD_STROBE()	{LCD_EN=1; NOP(); LCD_EN=0;} // vlozi na dane misto toto
//---------------------------------------------------------------------------//
void delayms(unsigned int ms)		//Ham delay ms
	{
		unsigned int count;
		
		T1CON = 0x00;				// Zdroj Fosc/4 bez delicky
		TMR1ON = 1;					// spusteni timeru
	
		for (count=0;count<ms;count++)
			{
				CLRWDT();
				TMR1ON = 0;
				TMR1L = 0x82;		// 1ms
				TMR1H = 0xEC;
				TMR1ON = 1;
				while (!TMR1IF);
				TMR1IF = 0;
			}
	}	
//---------------------------------------------------------------------------//
void LCD_Write(const char cw)
{
	char tmp;

	LCD_RW = 0;
	TRIS_LCD &= 0x0f; 						// nastav port RB4/7 jako OUT
	LCD_PORT = (LCD_PORT&0x0f)|(cw&0xf0);	// vynuluj datovej port, vynuluj spodni bity cw a horni bity zapis na port RB4/7
	LCD_STROBE(); 							// zapis horni bity
	LCD_PORT = (LCD_PORT&0x0f)|(cw<<4);		// vynuluj datovej port a zapis na nej spodni bity cw
	LCD_STROBE();
	TRIS_LCD |= 0xf0;						// nastav port RB4/7 jako IN
	LCD_RS = 0;
	LCD_RW = 1;

	do{
		LCD_STROBE();
		tmp = LCD_PORT;
		LCD_STROBE();
		tmp |= LCD_PORT>>4;
		CLRWDT();
	}while(tmp&0x80);
}
//---------------------------------------------------------------------------//
void LCD_WDATA(const char c)
{
	LCD_RS = 1;
	LCD_Write(c);
}
//---------------------------------------------------------------------------//
void LCD_WCMD(const char cmd)
{
	LCD_RS = 0;
	LCD_Write(cmd);
}
//---------------------------------------------------------------------------//
void LCD_Gotoxy(char x, char y)	// Pozice, radek
{
	char tg;
    switch (y){
		case 1:tg = x-1;
			break;
		case 2:tg = 0x40 + x - 1;
			break;
    }
	LCD_WCMD(tg|0x80);
}
//---------------------------------------------------------------------------//
void LCD_WriteString(const const char* s)
{
	char i, len = strlen(s);
	for(i=0;i<len;i++)  LCD_WDATA(s[i]);
}
//---------------------------------------------------------------------------//
void LCD_Init()				// 4 bit interface
{
	unsigned int n;
	
	TRIS_LCD = 0x00;
	delayms(20);			// wait 15ms or more after Vdd reaches 4.5V 
	LCD_RS		= 	0;
	LCD_RW		=	0;
	LCD_PORT	= 	 (LCD_PORT&0x0F)|0x30;
	LCD_STROBE();			//zapis dat (stejna data se v ruznych inter. zapisi)
	delayms(5);				//wait 4,1ms or more
	LCD_STROBE();			//opetovny	zapis dat
	n	=	DELAY_STROBE;	//wait more 100us - zde chyba!!!
	while(n--);
	LCD_STROBE();
	n	=	DELAY_STROBE;	//wait more 100us -konec prvni inicializace 3x
	while(n--);
	LCD_PORT	= (LCD_PORT&0x0F)|0x20;	// 4 bit interface				
	LCD_STROBE();
	n	= 	DELAY_STROBE;	//wait more 100us
	while(n--);
	LCD_WCMD(0x28);		// 4 BIT interface, 2 lines display, 5X7 c font 
	LCD_WCMD(0x08);		// display Off, cursor Off, blink off
	LCD_WCMD(0x01);		// Clears the display, returs the cursor to home
	LCD_WCMD(0x0c);		// On display, cursor Off, blink off
	LCD_WCMD(0x06);		// Cursor move Increment, Not to shift the display
	CLRWDT();
}
//---------------------------------------------------------------------------//
void LCD_PutChar(unsigned char ch)
{
	LCD_WDATA(ch);
}
//---------------------------------------------------------------------------//
void main(void)
{	
char	t=5;
char *p_t;
p_t = &t;


	TRISB3 = 0x00;
	RB3=1;
	LCD_Init();				//Khoi tao LCD
	
	LCD_Gotoxy(1,1);
    LCD_PutChar('5');
	
	LCD_Gotoxy(1,2);
	LCD_WriteString("T - Pozadovana");
	
	
	while (1) CLRWDT();
}