按键中断总结

一、RCC初始化

/****************************************************************************
* Function Name : RCC_Configuration
* Description : Sets System clock frequency to 72MHz and configure HCLK, PCLK2
* and PCLK1 prescalers.
* Input : None
* Output : None
* Return : None
****************************************************************************/
void RCC_Configuration(void)
{
    /* Deinitialize the RCC registers */
    RCC_DeInit();

    /* Enable the HSE */
    RCC_HSEConfig(RCC_HSE_ON);

    /* Wait till HSE is ready and if Time out is reached exit */
    HSEStartUpStatus = RCC_WaitForHSEStartUp();
    if(HSEStartUpStatus == SUCCESS)
    {
        /* Add here PLL ans system clock config */

        /* Enable The Prefetch Buffer */
        FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

        /* Configure Tthe Latency cycle: Set 0 Latency cycles */
        FLASH_SetLatency(FLASH_Latency_2);

        /* Configure HCLK such as HCLK = SYSCLK */
        RCC_HCLKConfig(RCC_SYSCLK_Div1);

        /* PCLK2 = HCLK */
        RCC_PCLK2Config(RCC_HCLK_Div1);

        /* PCLK1 = HCLK/2 */
        RCC_PCLK1Config(RCC_HCLK_Div2);

        /* Select HSE as system clock source*/
        RCC_SYSCLKConfig(RCC_SYSCLKSource_HSE);

        /* PLLCLK = 8MHz * 9 = 72MHz */
        RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

        /* ADCCLK = PCLK/4 */
        RCC_ADCCLKConfig(RCC_PCLK2_Div4);

        /* Enable PLL */
        RCC_PLLCmd(ENABLE);

        /* Wait till PLL is ready */
        while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);

        /* Select PLL as system clock source */
        RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); /* Wait till HSE is used as system clock source */
        while(RCC_GetSYSCLKSource() != 0x08)
        {

        }
    }
    else
    {
        /* If HSE fails to start-up. */
        while(1)
        {
        }
    }
}

相比之前的时钟初始化，多初始化了ADCCLK。

二、GPIO初始化

/****************************************************************************
* Function Name : GPIO_Configuration
* Description :
* Input : None
* Output : None
* Return : None
****************************************************************************/
void GPIO_Configuration(void)
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
}

使用PB8作为推挽输出，PB6为浮空输入。

三、NVIC初始化

/****************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures Vector Table base location.
* Input : None
* Output : None
* Return : None
****************************************************************************/
void NVIC_Configuration(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VET_TAB_RAM
    /* Set the Vector Table base location at 0x2000 0000 */
    NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else
    /* Set the Vector Table base location at 0x8000 0000 */
    NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

    NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

因位PB6位输入，也就是外部中断源。所以初始化EXTI9_5_IRQn作为外部中断源

四、EXTI初始化

/****************************************************************************
* Function Name : EXTI_PE6_Config
* Description :
* Input : None
* Output : None
* Return : None
****************************************************************************/
void EXTI_PE6_Config(void)
{
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource6);

    EXTI_InitStructure.EXTI_Line = EXTI_Line6;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    EXTI_GenerateSWInterrupt(EXTI_Line6);

}

设置了外部中断源，把GPIOB6作为中断源。外部中断线是6，结合原理图使用下降沿触发。
EXTI_GenerateSWInterrupt是触发一次软件中断。

同时需要编写中断函数在stm32f10x_it.c中：

/*******************************************************************************
* Function Name : EXTI9_5_IRQHandler
* Description : This function handles External lines 9 to 5 interrupt request.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void EXTI9_5_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line6) != RESET)
    {
        GPIO_WriteBit(GPIOB, GPIO_Pin_8, (BitAction)(1-GPIO_ReadOutputDataBit(GPIOB, GPIO_Pin_8)));

        EXTI_ClearITPendingBit(EXTI_Line6);
    }
}

五、main函数

/****************************************************************************
* Function Name : main
* Description : Main program.
* Input : None
* Output : None
* Return : None
****************************************************************************/
int main(void)
{
    RCC_Configuration();

    NVIC_Configuration();

    GPIO_Configuration();

    EXTI_PE6_Config();

    while(1)
    {
    }
}