/*
Pinout

1		VSS		GND
2		VDD		VDD
3		nc		nc
4 	RS		PD4
5		R/W		PD5
6		E			PD6
7		nc		nc
8		nc		nc
9		nc		nc
10	nc		nc
11	D4		PD0
12	D5		PD1
13	D6		PD2
14	D7		PD3
15	nc		nc
16	nc		nc

*/

#include "stm32f4xx.h"
uint32_t i;



void WriteNibble(char data){
	
	GPIOD->BSRRL |= data;
	GPIOD->BSRRH |= ~data;
	
	GPIOD->BSRRL |= (1<<6); //E=1;

	for (i=0;i<10000;i++){} //delay
		
	GPIOD->BSRRH |= (1<<6);	//E=0;
		
	for (i=0;i<10000;i++){} //delay
	
}

void WriteIns (char ins){
	GPIOD->BSRRH |= (1<<4); //RS=0;
	GPIOD->BSRRH |= (1<<5); //RW=0;
	
	WriteNibble((ins&0xF0)>>4); //High nibble
		
	WriteNibble(ins&0x0F); //Low nibble
		
}

void WriteData(char data){
	GPIOD->BSRRL |= (1<<4); //RS=1;
	GPIOD->BSRRH |= (1<<5); //RW=0;
	
	WriteNibble((data&0xF0)>>4); //High nibble
		
	WriteNibble(data&0x0F); //Low nibble
	
}


void initDispl(void){
	
	GPIOD->BSRRH |= (1<<4); //RS=0;
	GPIOD->BSRRH |= (1<<5); //RW=0;
	GPIOD->BSRRH |= (1<<6); //E=0;
	
	WriteNibble(0x03);		//Be sure to be in 8-Bit-Mode
	WriteNibble(0x03);
	WriteNibble(0x03);		
	WriteNibble(0x02);		//Switch to 4 Bit
	
	for (i=0;i<10000;i++){} //delay
		
	WriteIns(0x28);		//4-Bit-Mode
	WriteIns(0x08);		//display off
	WriteIns(0x06);		//entry mode set increment cursor by 1 not shifting display
	WriteIns(0x17);		//Character mode and internel power on
	WriteIns(0x01);	  //clear display
	WriteIns(0x02);   //return home
	WriteIns(0x0C);   //display on
}


int main ()
{
	//Taktversorgung Port D 
	RCC->AHB1ENR |= (1<<3);
	
	//Konfiguration Port D - Ausgaenge festlegen
	GPIOD->MODER |= (1<<0);
	GPIOD->MODER |= (1<<2);
	GPIOD->MODER |= (1<<4);
	GPIOD->MODER |= (1<<6);
	GPIOD->MODER |= (1<<8);
	GPIOD->MODER |= (1<<10);
	GPIOD->MODER |= (1<<12);
	GPIOD->MODER |= (1<<14);
	GPIOD->MODER |= (1<<16);
	
	//Initialisierung Display
	initDispl();
	
	//Anzeige "-" auf Display
	WriteData(0x2D);
	
	do
	{
		
	}
	while (1);
}