STM32简单的LED流水灯程序

//0x4002 1000 - 0x4002 13FF 复位和时钟控制(RCC)
#define RCC_BASE        0x40021000
#define RCC_APB2ENR        (RCC_BASE+0x18)
//LED接在GPIOF上，是APB2上的外设，是RCC_APB2ENR寄存器的第7位

//APB20x4001 1c00 GPIO端口F
#define GPIOF_BASE        0x40011c00
#define GPIOF_CHL        (0x000+GPIOF_BASE)
#define GPIOF_CHR        (0x004+GPIOF_BASE)
#define GPIOF_IDR        (0x008+GPIOF_BASE)
#define GPIOF_ODR         (0x00c+GPIOF_BASE)
#define GPIOF_BSRR         (0x010+GPIOF_BASE)
#define GPIOF_BRR        (0x014+GPIOF_BASE)
#define GPIOF_LCKR        (0x014+GPIOF_BASE)

void delay(int num)
{
    int i,j;
    for(i=0;i<num;i++)
        for(j=0;j<5000;j++)
            ;
}

int main(void)
{
    *(unsigned int *)RCC_APB2ENR=1<<7;//开gpiof时钟
    //设置gpiof的管脚为开漏输出，电平为0，外部电流灌入6，7，8，9管脚
    //设置成开漏输出，频率无所谓，那么cny为0101,mode为0101
    *(unsigned int *)GPIOF_CHL=0x55555555;
    *((unsigned int *)GPIOF_CHR)=0x55555555;
    *((unsigned int *)GPIOF_ODR)=0xffff;
    while(1)
    {
        *((unsigned int *)GPIOF_BSRR)=1<<22;
        delay(200);
        *((unsigned int *)GPIOF_BSRR)=1<<23;
        delay(200);
        *((unsigned int *)GPIOF_BSRR)=1<<24;
        delay(200);
        *((unsigned int *)GPIOF_BSRR)=1<<25;
        delay(200);
        *((unsigned int *)GPIOF_ODR)=0xffff;
        delay(200);
    }
}