1、GIPO端口初始化

本次实验采用GPIOA、GPIOB、GPIOC三个端口。该三个端口都属于APB2总线

找到端口偏移地址以及对应端口所在位置?

//----------------APB2使能时钟寄存器 ---------------------
#define RCC_APB2ENR		*((unsigned volatile int*)0x40021018)

	RCC_APB2ENR|=1<<2|1<<3|1<<4;			//APB2-GPIOA、GPIOB、GPIOC外设时钟使能

?本次实验采用通用推挽输出模式，最高输出时钟频率2Mhz。分别用到A4、B5、C14三个引脚。其中A4、B5属于端口配置低寄存器偏移地址为0x00，C13属于端口配置高寄存器偏移地址为0x04。

//----------------GPIOA配置寄存器 -----------------------
#define GPIOA_CRL		*((unsigned volatile int*)0x40010800)
//----------------GPIOB配置寄存器 -----------------------
#define GPIOB_CRL		*((unsigned volatile int*)0x40010C00)
//----------------GPIOC配置寄存器 -----------------------
#define GPIOC_CRH		*((unsigned volatile int*)0x40011004)

GPIOA_CRL&=0xFFF0FFFF;		//设置位 清零	
	GPIOA_CRL|=0x00020000;		//PA4推挽输出，把第19、18、17、16位变为0010
	
	GPIOB_CRL&=0xFF0FFFFF;		//设置位 清零	
	GPIOB_CRL|=0x00200000;		//PB5推挽输出，把第23、22、21、20变为0010
	 
	GPIOC_CRH&=0xFF0FFFFF;		//设置位 清零	
	GPIOC_CRH|=0x00200000;		//PC14推挽输出，把第23、22、21、20变为0010

实现代码

C语言

#include "stm32f10x.h"
//----------------APB2??????? ---------------------
#define RCC_APB2ENR		*((unsigned volatile int*)0x40021018)
//----------------GPIOA????? -----------------------
#define GPIOA_CRL		*((unsigned volatile int*)0x40010800)
#define	GPIOA_ODR		*((unsigned volatile int*)0x4001080C)
//----------------GPIOB????? -----------------------
#define GPIOB_CRL		*((unsigned volatile int*)0x40010C00)
#define	GPIOB_ODR		*((unsigned volatile int*)0x40010C0C)
//----------------GPIOC????? -----------------------
#define GPIOC_CRH		*((unsigned volatile int*)0x40011004)
#define	GPIOC_ODR		*((unsigned volatile int*)0x4001100C)

extern void led(void);
//????
 void Delay()
 {
   u32 i=0;
   for(;i < 5000000;i++);
 }
 int main(void)
 {	
	 led();
	RCC_APB2ENR|=1<<2|1<<3|1<<4;			//APB2-GPIOA?GPIOB?GPIOC??????	
	
	GPIOA_CRL&=0xFFF0FFFF;		//??? ??	
	GPIOA_CRL|=0x00020000;		//PB5????
	GPIOA_ODR&=~(1<<4);			//???????
	
	GPIOB_CRL&=0xFF0FFFFF;		//??? ??	
	GPIOB_CRL|=0x00200000;		//PB5????
	GPIOB_ODR&=~(1<<5);			//???????
	 
	GPIOC_CRH&=0xF0FFFFFF;		//??? ??	
	GPIOC_CRH|=0x02000000;		//PB5????
	GPIOC_ODR&=~(1<<14);			//???????		
	 

	 

	while(1){

		//A?
		GPIOA_ODR|=1<<4;		//PB5???
	 	Delay();
		GPIOA_ODR&=~(1<<4);		//PB5???,????0,??????
		Delay();

		
		//B?
		GPIOB_ODR|=1<<5;		//PB5???
	 	Delay();
		GPIOB_ODR&=~(1<<5);		//PB5???,????0,??????
		Delay();

		
		
		//C?
		GPIOC_ODR|=1<<14;		//PB5???
	 	Delay();
		GPIOC_ODR&=~(1<<14);		//PB5???,????0,??????
		Delay();

		}
}