#include <stdio.h>
// Where is the led is connected
// Port:A
// Pin:PA5

#define PERIPH_BASE 				      (0x40000000UL)
#define IOPORTPERIPH_OFFSET 			(0x10000000UL)
#define AHBPERIPH_OFFSET          (0X20000UL)
#define AHBPERIPH_BASE            (PERIPH_BASE       +  AHBPERIPH_OFFSET)
#define IOPORTPERIPH_BASE				  (PERIPH_BASE       + IOPORTPERIPH_OFFSET)
#define GPIOA_OFFSET				      (0x0000U)
#define GPIOA_BASE 					      (IOPORTPERIPH_BASE + GPIOA_OFFSET)
#define RCC_OFFSET					      (0x21000U)
#define RCC_BASE					        (AHBPERIPH_BASE    +  RCC_OFFSET)
#define IOPAEN_R_OFFSET 			      (0x2CUL)
#define RCC_IOPAEN_R			        (*(volatile unsigned int*)(RCC_BASE+IOPAEN_R_OFFSET))
#define GPIOAEN						        (1U<<0)
#define MODE_R_OFFSET 			    	(0x00UL)
#define GPIOA_MODE_R				      (*(volatile unsigned int*)(GPIOA_BASE + MODE_R_OFFSET))
#define OD_R_OFFSET 				      (0x14UL)
#define GPIOA_OD_R					      (*(volatile unsigned int*)(GPIOA_BASE + OD_R_OFFSET))
#define PIN5 						          (1UL<<5)
#define LED_PIN					        	PIN5


void setup() 
{
	/*1.Enable clock to access the GPIOA port*/
	RCC_IOPAEN_R	|=GPIOAEN;
	/*2. Set PIN5 as output*/
	GPIOA_MODE_R |=(1<<10);
	GPIOA_MODE_R &=~(1<<11);
	while(1)
	{
		// toggle the LED
		GPIOA_OD_R ^=LED_PIN	;
		for(long  i=0;i<1000000;i++);

	}
}

void loop() 
{

}