#include <bcm2835.h>
#include <stdio.h>

#define D0 6
#define D1 5
#define D2 13
#define D3 19
#define D4 26
#define D5 21
#define D6 20
#define D7 16

#define RS 17
#define RW 27
#define E  22
int data_pin[]={D0,D1,D2,D3,D4,D5,D6,D7};

char lcdbuf[]={"hello Raspberry!"};
#define LEAVE_CHAR (16-(sizeof(lcdbuf)-1))
void display_string(int x,int y,char *s);
void display_xy(int x,int y);
void lcd_dataWrite(char data);
void WriteDatalcd(char Wdata);
void lcd_init(void);
void WriteCommandlcd(char Wdata);
void gpio_init(void);
void display_char(int x,int y,char s);
void move_display(void);

int main(int argc, char **argv)
{
	

    if (!bcm2835_init())return 1;
    	
	gpio_init();
	
	lcd_init();
	
	while(1)
	{
	
			WriteCommandlcd(0x01);//clear screen
			
		
		move_display();
					
		bcm2835_delay(500);

  }
  
  
   bcm2835_close();

  return 0;
	
	
}

void lcd_init(void)
{
	bcm2835_delay(10);
	
	WriteCommandlcd(0x38);
	bcm2835_delay(10);
	WriteCommandlcd(0x38);
		bcm2835_delay(10);
		WriteCommandlcd(0x38);
		bcm2835_delay(10);

	WriteCommandlcd(0x06);//
		bcm2835_delay(10);
	WriteCommandlcd(0x0c);
		bcm2835_delay(10);
	WriteCommandlcd(0x01);
	
	
	
	
}

void WriteCommandlcd(char Wdata)//write command to LCD
{
		
	
		bcm2835_gpio_write(RS, LOW);
		bcm2835_gpio_write(RW, LOW);
		bcm2835_gpio_write(E, HIGH);
		
		lcd_dataWrite(Wdata);
		bcm2835_delay(10);
		bcm2835_gpio_write(E,LOW);
	
	
	
}

void WriteDatalcd(char Wdata)//write date to LCD
{
	
	
		bcm2835_gpio_write(RS, HIGH);
		bcm2835_gpio_write(RW, LOW);
		bcm2835_gpio_write(E, HIGH);
		
		lcd_dataWrite(Wdata);
		bcm2835_delay(10);
		bcm2835_gpio_write(E, LOW);
	
	
	
}

void lcd_dataWrite(char data)//write date to D0~D7
{
	int i,move=0x80;
	
	for(i = 7; i >=0; i--)
			{
				if(data&move)	
					{
						bcm2835_gpio_write(data_pin[i], HIGH);
						//printf("1");
					}
				else
					{
						bcm2835_gpio_write(data_pin[i], LOW);
						//printf("0");
					}
				move=move>>1;
				
				
			}
	  // printf("\r\n");
	
}

void display_xy(int x,int y)//set start location
{
	if(y==1)
		x+=0x40;
	
	x+=0x80;
			
	WriteCommandlcd(x);
	
	
	
}


void display_string(int x,int y,char *s)//display string
{
	display_xy(x,y);
	while(*s)
	{
		WriteDatalcd(*s);
		s++;
		
	}	
	
}

void display_char(int x,int y,char s)//display single char
{
	display_xy(x,y);

		WriteDatalcd(s);
		
	
}

void gpio_init(void)
{
	int i=8;
	
	  while(i--)
	  {
		 bcm2835_gpio_fsel(data_pin[i], BCM2835_GPIO_FSEL_OUTP);
		 
	  }
		
  	bcm2835_gpio_fsel(RS, BCM2835_GPIO_FSEL_OUTP);
  	bcm2835_gpio_fsel(E, BCM2835_GPIO_FSEL_OUTP);
  	bcm2835_gpio_fsel(RW, BCM2835_GPIO_FSEL_OUTP);
	
	
}


void move_display(void)//word move display
{
	
	static int x=0,y=0,i;
	
		if(x>=16&&y==0)
			{
				y=1;
				x=0;
			}
		else if(x>=16&&y==1)
			{
					y=0;
					x=0;
			}
				
				
			if(x>=LEAVE_CHAR&&y==0)
				{
					i=0;
					while(i<(x-LEAVE_CHAR))
					{
					display_char(i,1,lcdbuf[(sizeof(lcdbuf)-1)-(x-LEAVE_CHAR)+i]);
					i++;
				}
				}
				
				
				if(x>=LEAVE_CHAR&&y==1)
				{
					i=0;
					while(i<(x-LEAVE_CHAR))
					{
					display_char(i,0,lcdbuf[(sizeof(lcdbuf)-1)-(x-LEAVE_CHAR)+i]);
					i++;
				}
				}
				display_string(x,y,lcdbuf);
				x++;
				
	
	
}