[嵌入式]STM32寄存器开发之KEY控制LED

一、前期准备：

1、STM32F4xx中文参考手册.pdf
先上代码

#include "stm32f4xx.h"  

#define  RCC_AHB1ENR	( *(volatile unsigned int *)(0x40023800 + 0x30) )  //AHB1时钟使能寄存器

#define  GPIOF_MODER	( *(volatile unsigned int *)(0x40021400 + 0x00) )  //GPIOF端口模式寄存器
#define  GPIOF_OTYPER	( *(volatile unsigned int *)(0x40021400 + 0x04) )  //GPIOF端口输出类型寄存器
#define  GPIOF_OSPEEDR	( *(volatile unsigned int *)(0x40021400 + 0x08) )  //GPIOF端口输出速度寄存器
#define  GPIOF_PUPDR	( *(volatile unsigned int *)(0x40021400 + 0x0C) )  //GPIOF端口上下拉寄存器
#define  GPIOF_ODR		( *(volatile unsigned int *)(0x40021400 + 0x14) )  //GPIOF端口输出数据寄存器


#define  GPIOA_MODER	( *(volatile unsigned int *)(0x40020000 + 0x00) )  //GPIOA端口模式寄存器
#define  GPIOA_IDR		( *(volatile unsigned int *)(0x40020000 + 0x10) )  //GPIOA输入数据寄存器
	
int main()
{
	//1.打开时钟  GPIOF PF9  GPIOA PA0
//	RCC_AHB1ENR |= (1<<5);
//	RCC_AHB1ENR |= (1<<0);
	
	RCC->AHB1ENR |= (1<<5);
	
	
	//2.配置PF9  PA0
	GPIOF_MODER |= 	(1<<18);
	GPIOF_MODER &= ~(1<<19);    //输出模式
	
	GPIOF_OTYPER &= ~(1<<9);  	//推挽输出
 
	GPIOF_OSPEEDR |= (3<<18);	//输出速率
	
	GPIOF_PUPDR |= 	(1<<18);
	GPIOF_PUPDR &= ~(1<<19);	//上拉输出
	
	GPIOA_MODER &= ~(1<<0);
	GPIOA_MODER &= ~(1<<1);    //输入模式
	
	GPIOF_ODR |=  (1<<9);	//输出低电平 灯灭
	
	while(1)
	{
		if( GPIOA_IDR & 0x1 )
		{
			GPIOF_ODR &= ~(1<<9);	//输出低电平 灯亮
		}			
		else
		{
			GPIOF_ODR |=  (1<<9);	//输出低电平 灯灭
		}			
	}
}

这个代码是基于STM32寄存器开发之点亮led灯 的基础上做了调整，用按键实现点亮led灯，本文章仅介绍按键部分的代码。

#define  GPIOA_MODER	( *(volatile unsigned int *)(0x40020000 + 0x00) )  //GPIOA端口模式寄存器

章节：2.3 存储器映射
上图得知GPIOA的起始地址是0x40020000

因为按键的串口位置是PF0，它在0位置

#define  GPIOA_IDR		( *(volatile unsigned int *)(0x40020000 + 0x10) )  //GPIOA输入数据寄存器

输入数据寄存器偏移地址是0x10

GPIOA_MODER &= ~(1<<0);
GPIOA_MODER &= ~(1<<1);    //输入模式

	while(1)
	{
		if( GPIOA_IDR & 0x1 )
		{
			GPIOF_ODR &= ~(1<<9);	//输出低电平 灯亮
		}			
		else
		{
			GPIOF_ODR |=  (1<<9);	//输出低电平 灯灭
		}			
	}