Detailed explanation of exit interrupt

EXIT Interrupt details ：

EXIT Structure ：

typedef struct
{
    
  uint32_t EXTI_Line;               /*!< Specifies the EXTI lines to be enabled or disabled. This parameter can be any combination of @ref EXTI_Lines */
   
  EXTIMode_TypeDef EXTI_Mode;       /*!< Specifies the mode for the EXTI lines. This parameter can be a value of @ref EXTIMode_TypeDef */

  EXTITrigger_TypeDef EXTI_Trigger; /*!< Specifies the trigger signal active edge for the EXTI lines. This parameter can be a value of @ref EXTIMode_TypeDef */

  FunctionalState EXTI_LineCmd;     /*!< Specifies the new state of the selected EXTI lines. This parameter can be set either to ENABLE or DISABLE */ 
}EXTI_InitTypeDef;

1.EXTI_Line： To interrupt / Event line selection , All in all 20 A break line is ( stm32f10x_exit.h ) You can view in the header file .(EXIT0—EXIT19)

2.EXIT_Mode: Interrupt mode selection , The optional mode is generate interrupt / Produce an event

3.EXIT_Trigger : Edge triggered events , Optional rising edge trigger , Falling edge trigger , Or both rising and falling edges trigger

4.EXIT_LineCmd : Control whether to enable EXIT Line

NVIC Structure ：

stay (misc.h) Header file

typedef struct
{
    
  uint8_t NVIC_IRQChannel;                    /*!< Specifies the IRQ channel to be enabled or disabled. This parameter can be a value of @ref IRQn_Type (For the complete STM32 Devices IRQ Channels list, please refer to stm32f10x.h file) */

  uint8_t NVIC_IRQChannelPreemptionPriority;  /*!< Specifies the pre-emption priority for the IRQ channel specified in NVIC_IRQChannel. This parameter can be a value between 0 and 15 as described in the table @ref NVIC_Priority_Table */

  uint8_t NVIC_IRQChannelSubPriority;         /*!< Specifies the subpriority level for the IRQ channel specified in NVIC_IRQChannel. This parameter can be a value between 0 and 15 as described in the table @ref NVIC_Priority_Table */

  FunctionalState NVIC_IRQChannelCmd;         /*!< Specifies whether the IRQ channel defined in NVIC_IRQChannel will be enabled or disabled. This parameter can be set either to ENABLE or DISABLE */   
} NVIC_InitTypeDef;

1.NVIC_IRQChannel : Set interrupt channel

2.NVIC_IRQChannelPreemptionnPriority : Set preemption priority

3.NVIC_IRQChannelSubPriority : Set sub priority

4.NVIC_IRQChannelCmd: Control whether to enable Interrupt controller

The following table gives the basis NVIC_PriorityGroupConfig Function to configure the allowed priority and secondary priority values

NVIC_PriorityGroup	NVIC_IRQChannelPreemptionPriority	NVIC_IRQChannelSubPriority	Description
NVIC_PriorityGroup_0	0	0-15	0 bits for pre-emption priority 4 bits for subpriority
NVIC_PriorityGroup_1	0-1	0-7	1 bits for pre-emption priority 3 bits for subpriority
NVIC_PriorityGroup_2	0-3	0-3	2 bits for pre-emption priority 2 bits for subpriority
NVIC_PriorityGroup_3	0-7	0-1	3 bits for pre-emption priority 1 bits for subpriority
NVIC_PriorityGroup_4	0-15	0	4 bits for pre-emption priority 0 bits for subpriority

As can be seen from the table, first compare the preemption priority NVIC_IRQChannelPreemptionPriority The smaller the number, the better , Then compare the sub priorities NVIC_IRQChannelSubPriority It's the same thing .

How to configure interrupt function ：

1. Initializes the used to interrupt GPIO

2. initialization EXIT ( Edge detection circuit ----> Rising edge / Falling edge trigger interrupt )

3. To configure NVIC( Interrupt priority )

4. Write service functions ( It can be found in the startup file startup_stm32f10x_hd.s Find )

Interrupt procedure and IO To configure ：

#include "exit.h"
void Exit_config_Iinit(void)
{
    
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);// Interrupt bit multiplexing, so turn on the multiplexing clock 
    // To configure GPIO
    GPIO_InitTypeDef Gpio_Init;
    Gpio_Init.GPIO_Mode = GPIO_Mode_IPD;
    Gpio_Init.GPIO_Pin = GPIO_Pin_1;
    Gpio_Init.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(GPIOA,&Gpio_Init);
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource1);//GPIO Configuration of interrupt line 
    // To configure EXTI External interrupt 
    EXTI_InitTypeDef Exit_Init;
    Exit_Init.EXTI_Line = EXTI_Line1;
    Exit_Init.EXTI_Mode = EXTI_Mode_Interrupt;
    Exit_Init.EXTI_Trigger = EXTI_Trigger_Falling;
    Exit_Init.EXTI_LineCmd = ENABLE;
    EXTI_Init(&Exit_Init);
    // Configure the interrupt controller 
    NVIC_InitTypeDef Nvic_Init;
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
    Nvic_Init.NVIC_IRQChannel = EXTI1_IRQn;
    Nvic_Init.NVIC_IRQChannelPreemptionPriority = 1;
    Nvic_Init.NVIC_IRQChannelSubPriority = 1;
    Nvic_Init.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&Nvic_Init);
}

Interrupt service function configuration ：

void EXTI1_IRQHandler(void)
{
    
    if(EXTI_GetITStatus(EXTI_Line1) != RESET)// Determine whether an interruption has occurred 
    {
    
        GPIO_ResetBits(GPIOC,GPIO_Pin_13);
        delay(1000);
        GPIO_SetBits(GPIOC,GPIO_Pin_13);
    }
    EXTI_ClearFlag(EXTI_Line1);// Clears the interrupt flag bit 
}

The rising edge of the above interrupt is triggered and lit LED Pause 1s Put out after .