STM32 - introduction of external interrupts exti and NVIC

STM32—— External interrupt EXTI and NVIC Introduction to

What interruption is ？

Stop what you are doing and get busy with something else , After you finish your work, come back and continue to do what you are doing

Interrupt what you did ——> Interrupt work

Keep the scene —— Keep the work progress

Handling interrupts ——> The conversation

Back to the scene ——> Keep working

How to configure interrupts

1、 Initializes the used to interrupt GPIO mouth

2、 initialization EXTI（ What is? EXTI？）

Edge detection circuit ——> Rising edge / Falling edge trigger interrupt

EXTI Is an external interrupt source , Yes 20 Interrupt or event line

3、 To configure NVIC （ Interrupt priority ）

Configure interrupt priority , Break nesting

4、 Write interrupt service function

EXTI Structure

1、EXTI_Line：EXTI interrupt / Event line selection , Optional EXTI0 to EXTI19(stm32f10x_exti.h)

2、EXTI_Mode: EXTI Mode selection , The optional mode is generate interrupt / Produce an event

3、EXTI_Trigger: EXTI Edge triggered events , Optional rising edge trigger , Falling edge trigger Or both rising and falling edges trigger

4、EXTI_LineCmd: Control whether to enable EXTI Line , Can make EXTI Line or disable .

typedef struct
{
    
  uint32_t EXTI_Line;           /* Select the break line */  
   
  EXTIMode_TypeDef EXTI_Mode;     /* Select shielding ; Interrupt frequency closure 、 Event masking */ 

  EXTITrigger_TypeDef EXTI_Trigger; /* Select trigger mode ： Rising edge 、 Falling edge 、 Software interruption events */

  FunctionalState EXTI_LineCmd;     /* Can make */
}EXTI_InitTypeDef;

NVIC Structure

typedef struct
{
    
  uint8_t NVIC_IRQChannel;                    

  uint8_t NVIC_IRQChannelPreemptionPriority;  

  uint8_t NVIC_IRQChannelSubPriority;         

  FunctionalState NVIC_IRQChannelCmd;        
} NVIC_InitTypeDef;

1、NVIC_IRQChannel: Set interrupt channel （misc.h）

2、NVIC_IRQChannelPreemptionPriority: Set preemption priority

3、NVIC_IRQChannelSubPriority: Set sub priority

4、NVIC_IRQChannelCmd: Control whether to enable Interrupt controller , Can make Or disable .