STM32 - external interrupt application (exti) (use cubemx to configure interrupts)

stay STM32 in , Most events are invisible , But almost all events are bound with terminal functions , So we usually turn on the interrupt function to use the corresponding event

EXTI： Expand interrupt and event controllers , yes stm32 A peripheral on , It can capture some events such as the level change of external input line ,EXTI After capturing the event , You can also generate corresponding EXTI Some terminals of interrupts and so on

EXTI Of 2 Features ： Capture events such as external input , Generate EXTI Interrupt and other interrupt requests

  When the level of the input line changes , It will be detected by the edge detection circuit , Then the rising edge trigger selector and the falling edge trigger selector will select this signal , For example, the falling edge trigger register is set , At the same time, the edge detection circuit detects that the level is changed by 1-0, Then this signal will pass through the OR gate , This is the hardware trigger , alike , The interrupt request of the software interrupt event register can also pass through the OR gate , It is called software trigger , The signal passes through the OR gate , If the event shield does not shield the signal , Then the signal will reach the pulse generator , Initiate interrupt request , Goods wake up CPU, The interrupt request will reach the request pending register through the OR gate , If the interrupt mask register does not mask the request suspend register , This interrupt request will be sent to NVIC

Use CubeMX Configure interrupts

1. First, configure the system clock , Select the external crystal oscillator

2. Set the maximum frequency

 3. Get into GPIO, Start interrupt configuration , Click on any pin , choice EXTI term

 

We can refer to the reference manual , Know which event line the pin is on

 

 4. Set the trigger mode

 5. Set interrupt priority

 6. Code output settings

 7. The generated code

The automatically generated code has completed the configuration just now

  The generated code can be copied into your own project

  The triggering process of interruption ：

Trigger EXTI interrupt ,CPU Get the offset stored in the interrupt vector table , That's the entry address , Finally, jump to the interrupt service function

The following are the service functions in the interrupt vector table , When an interrupt is triggered ,CPU It'll be here , Offset according to the terminal number , Get the offset address ,EXTI Be triggered , It will jump to the red box in the following figure