Stm32F407——控制一颗LED发光二极管闪烁(1)

Myth丶恋晨 2022-10-17 00:43 217阅读 0赞

> 1、一个LED灯闪烁

//GPIOF口相关寄存器的定义
    //端口x输入输出模式配置寄存器，控制位=00输入，=01通用输出，=10复用，=11模拟
    #define GPIOF_MODER (*(volatile unsigned *)0x40021400) 
    //端口输出类型配置寄存器。=0推挽输出，=1开漏输出 
    #define GPIOF_OTYPER (*(volatile unsigned *)0x40021404) 
    //端口x输出速度配置寄存器。=00，2MHz；=01，25M；=10，50M；=11，30pF时为100M.
    #define GPIOF_OSPEEDR (*(volatile unsigned *)0x40021408) 
    //端口上拉下拉配置寄存器。=00无上下拉，=01上拉，=10下拉，=11保留
    #define GPIOF_PUPDR (*(volatile unsigned *)0x4002140C) 
    //端口输出数据寄存器，某位=0对应端口输出低电平，=1输出高电平。
    #define GPIOF_ODR (*(volatile unsigned *)0x40021414) 
    //时钟系统相关寄存器的定义，外设时钟使能寄存器:=1对应外设时钟使能
    #define RCC_AHB1ENR (*(volatile unsigned *)0x40023830) 
    
    #define u8 unsigned char
    #define u16 unsigned short
    #define u32 unsigned int
    void Led_Init(void);
    void delay(void);
    int main(void)
    {  
    		Led_Init();				//初始化LED接口,LED0接PF9
    		while(1)
    		{ 
    			GPIOF_ODR &= ~(1<<9); //LED0亮
    			delay();              //延时 
    			GPIOF_ODR |= (1<<9);  //LED0灭
    			delay();              //延时
    		}
    }
    //-----------------led0初始化函数定义-------------------
    void Led_Init(void)
    {     	 
    		RCC_AHB1ENR |= 1<<5;         //使能PORTF时钟 
    		GPIOF_MODER &= ~(3<<(9*2));  //将配置PF9引脚相关位bit18,bit19清0
    		GPIOF_MODER |= (1<<(9*2));   //配置PF9为输出
    	
    		GPIOF_OTYPER &= ~(1<<9);     //电路工作方式为推挽
    	
    		GPIOF_OSPEEDR &= ~(3<<(9*2));//对应位清0 ？？？
    		GPIOF_OSPEEDR |= (2<<(9*2)); //响应速度50M，其他值亦可
    	
    		GPIOF_PUPDR &= ~(3<<(9*2));  //清0
    		GPIOF_PUPDR |= (1<<(9*2));   //上拉有效
    }
    //---------------------延时函数定义---------------------
    void delay(void)
    { 
    	u32 i, j;
    	for(i=0; i<200; i++)	//200*5000=1000000us=1000ms=1s
    		for(j=0; j<5000; j++);
    }

> 2、外加系统时钟初始化函数

//---------------------------------------------------------- 
    u8 Sys_Clock_Set(u32 plln,u32 pllm,u32 pllp,u32 pllq)
    {  
    		u16 retry=0;
    		u8 status=0;
    		RCC_CR |= 1<<16;				//HSE 开启 
    		while(((RCC_CR&(1<<17))==0)&&(retry<0X1FFF)) retry++;//等待HSE RDY
    		if(retry==0X1FFF) status=1;	    //HSE无法就绪
    		else   
    		{ 
    			RCC_APB1ENR |= 1<<28;	   //电源接口时钟使能
    			PWR_CR |= 3<<14; 		   //高性能模式,时钟可到168Mhz
    			RCC_CFGR |= (0<<4)|(5<<10)|(4<<13);//HCLK 不分频;APB1 4分频;APB2 2分频. 
    			RCC_CR &= ~(1<<24);	  //关闭主PLL
    			RCC_PLLCFGR = pllm|(plln<<6)|(((pllp>>1)-1)<<16)|(pllq<<24)|(1<<22);//配置主PLL,PLL时钟源来自HSE
    			RCC_CR |= 1<<24;			//打开主PLL
    			while((RCC_CR & (1<<25))==0);//等待PLL准备好 
    			FLASH_ACR |= 1<<8;		    //指令预取使能.
    			FLASH_ACR |= 1<<9;		    //指令cache使能.
    			FLASH_ACR |= 1<<10;		//数据cache使能.
    			FLASH_ACR |= 5<<0;		    //5个CPU等待周期. 
    			RCC_CFGR &= ~(3<<0);		//清零
    			RCC_CFGR |= 2<<0;		    //选择主PLL作为系统时钟 
    			while((RCC_CFGR&(3<<2))!=(2<<2));//等待主PLL作为系统时钟成功. 
    		} 
    		return status;
    } 
    //----------------------------------------------------------
    void Stm32_Clock_Init(u32 plln,u32 pllm,u32 pllp,u32 pllq)
    {   
    		RCC_CR|=0x00000001;		//设置HSISON,开启内部高速RC振荡
    		RCC_CFGR=0x00000000;		//CFGR清零 
    		RCC_CR&=0xFEF6FFFF;		//HSEON,CSSON,PLLON清零 
    		RCC_PLLCFGR=0x24003010;	//PLLCFGR恢复复位值 
    		RCC_CR&=~(1<<18);			//HSEBYP清零,外部晶振不旁路
    		RCC_CIR=0x00000000;		//禁止RCC时钟中断 
    		Sys_Clock_Set(plln,pllm,pllp,pllq);//设置时钟 
    }