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/**
 ******************************************************************************
 * @file           : main.c
 * @author         : Auto-generated by STM32CubeIDE
 * @brief          : Main program body
 ******************************************************************************
 * @attention
 *
 * Copyright (c) 2023 STMicroelectronics.
 * All rights reserved.
 *
 * This software is licensed under terms that can be found in the LICENSE file
 * in the root directory of this software component.
 * If no LICENSE file comes with this software, it is provided AS-IS.
 *
 ******************************************************************************
 */

#include <stdint.h>
#include <stdio.h>


#define RCC 0x40023800
#define RCC_AHB1ENR (RCC + 0x30)
#define RCC_CFGR (RCC + 0x08)
#define RCC_CR (RCC + 0x00)

#define GPIOA 0x40020000
#define GPIOA_MODER (GPIOA + 0x00)
#define GPIOA_OSPEEDR (GPIOA + 0x08)
#define GPIOA_ODR (GPIOA + 0x14)
#define GPIOA_OTYPER (GPIOA + 0x04)

void delay() {
	for (int i = 0; i < 800000; i++);
}

int main(void)
{
	uint32_t* rccAhb1enr = (uint32_t*) (RCC_AHB1ENR);
	uint32_t* rccCfgr = (uint32_t*) (RCC_CFGR);
	uint32_t* rccCr = (uint32_t*) (RCC_CR);

	uint32_t* gpioaModer = (uint32_t*) (GPIOA_MODER);
	uint32_t* gpioaOspeedr = (uint32_t*) (GPIOA_OSPEEDR);
	uint32_t* gpioaOdr = (uint32_t*) (GPIOA_ODR);
	uint32_t* gpioaOtyper = (uint32_t*) (GPIOA_OTYPER);

    // Enable HSE on
    *rccCr |= (1 << 16);

    // Wait until the HSE Clock stabled
	while(!(*rccCr & (1 << 17)));

   // Switch the system clock to HSE
   *rccCfgr &= ~(0b11);
   *rccCfgr |= (0b10);

	// IO port A clock enable
	*rccAhb1enr |= (1 << 0);

	// Configure the corresponding PA5 as output
	*gpioaModer &= ~(0b11 << 10);
	*gpioaModer |= (0b01 << 10);

	// Configure the type for the output pin
	*gpioaOtyper &= ~(0b11 << 10);
	*gpioaOtyper |= (0b01 << 10);

	// Configure the speed for the output pin
	*gpioaOspeedr &= ~(0b11 << 10);
	*gpioaOspeedr |= (0b10 << 10);

    while (1) {
    	// Turn on the portA5 and wait
    	*gpioaOdr |= (1 << 5);
    	delay();

    	// Turn off the portA5 and wait
    	*gpioaOdr &= ~(1 << 5);
    	delay();
    }
}