#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 GPIOAEN						        (1U<<0)
#define PIN5 						          (1UL<<5)
#define LED_PIN					        	PIN5

typedef struct {
	volatile uint32_t DUMMY[12];
	volatile uint32_t AHB1ENR;
}RCC_typeDef;

typedef struct
{
	volatile uint32_t  MODER;
	volatile uint32_t  DUMMY[4];
	volatile uint32_t  ODR;

}GPIO_typeDef;

#define GPIOA	((GPIO_typeDef *)GPIOA_BASE)
#define RCC		((RCC_typeDef *)RCC_BASE)

void setup() 
{
/*1.Enable clock to access the GPIOA port*/
	RCC->AHB1ENR |=GPIOAEN;
	/*2. Set PIN5 as output*/
	GPIOA->MODER  |=(1<<10);
	GPIOA->MODER  &=~(1<<11);
	while(1)
	{
		// toggle the LED
		GPIOA->ODR ^=LED_PIN	;
		for(long i=0;i<1000000;i++);
  }
}

void loop() 
{

}