//PA0 -PA7 - D0-D7 IN LCD - Output
//PB5 -RS - Output
//PB6 -RW - Output
//PB7 -EN - Output

#include <stdint.h>
//#include <stdio.h>
#include "STM32C031C6.h"

#define RS 0x20 //0010 0000 - PB5
#define RW 0x40 //0100 0000 - PB6
#define EN 0x80 //1000 0000 - PB7

unsigned char Message1[]=("HELLO WORLD...");
unsigned char Message2[]=("HAPPY CODING...");

void GPIO_Inits(void);
void LCD_Command(unsigned char command);
void LCD_Data(unsigned char data);
void LCD_Init(void);
void delayMs(int delay);

int main(void)
{

	LCD_Init();
	
	while(1)
	{
		unsigned char i=0,j=0;
		LCD_Command(0x80); //First line Initialization (turn display)
		delayMs(15);
		while (Message1[i]!='\0')
		{
			LCD_Data(Message1[i]);
			i++;
			delayMs(200);
		}
		delayMs(1000);

		LCD_Command(0xC0); //Second line Initialization (turn display)
		delayMs(15);
		while (Message2[j]!='\0')
		{
			LCD_Data(Message2[j]);
			j++;
			delayMs(200);
		}
		delayMs(1000);

		LCD_Command(0x01); //clear screen move cursor home
		delayMs(15);
	} 

	return 0;
}

void GPIO_Inits(void)
{ 
	RCC->IOPENR |= 0x03; //0011 - GPIOBEN(1) , GPIOAEN(0)

	//PB5,PB6,PB7 - Output(01)
	GPIOB->MODER &= 0x03FF; //0000 0011 1111 1111 - (7654 3210)
	GPIOB->MODER |= 0x5400; //0101 0100 0000 0000 - (7654 3210)

	//EN(PB7) and RW(PB6) Low ==> (pin 31-16)->RESET, (pin 15-0) -> SET
	GPIOB->BSRR = 0x00C00000; // 1100 0000 0000 0000 0000 0000

	//PA0 -PA7 - Output(01)
	GPIOA->MODER &= 0xFFFF0000; //0000 0000 0000 0000
	GPIOA->MODER |= 0x00005555; //0101 0101 0101 0101
}

void LCD_Command(unsigned char command)
{
	//printf("command is A %u B - ",(unsigned char)command);
	//printf("command is C %02X D\n",(unsigned int)command);
	// RS=0 -> Command,  RW=0 -> Write
	GPIOB->BSRR=(RS|RW)<<16;

	//PA0 -PA7 => Output
	GPIOA->ODR=command;

	GPIOB->BSRR=EN ; //ENABLE EN
	delayMs(15);
	GPIOB->BSRR=EN<<16 ; //clear EN
	//delayMs(30);
}

void LCD_Data(unsigned char data)
{
	//RS=1 -> Data
	GPIOB->BSRR=RS;	
	//RW=0 -> Write
	GPIOB->BSRR=RW<<16;

	//PA0 -PA7 => Output
	GPIOA->ODR=data;

	GPIOB->BSRR=EN ; //ENABLE EN
	delayMs(30);
	GPIOB->BSRR=EN<<16 ; //clear EN
	delayMs(30);
}

void LCD_Init(void)
{
	GPIO_Inits();
	//any one Command works well for wake up command - (0x33) or (0x32)
	LCD_Command(0x33); //Wake up
		delayMs(15);
	LCD_Command(0x32); //Wake up
		delayMs(15);
	LCD_Command(0x38); //select one line
	delayMs(15);
	LCD_Command(0x0C); //Display ON, set b it data mode
	delayMs(15);
	LCD_Command(0x06); //move the cursor left to right
	delayMs(15);
	LCD_Command(0x01); //clear screen move cursor home
	delayMs(15);
	delayMs(5000);
}

void delayMs(int delay)
{
	int i;
	for (;delay>0;delay--)
	{
		for(i=0;i<3195;i++)
		{

		}
	}
}