Just learning embedded, I want to ask what is interrupt and what is the concept of interrupt

A simple life scene ： The child sleeps in the bedroom , Mother is reading in the living room , that , How does a mother know her child is awake ？

·  Always check in the room ： A query

·  Go into the room and sleep with the children , When a child wakes up, it will wake her up ： Sleep - Wake up the

·  Mom has a lot of work to do , But you can set an alarm clock to sleep with your child ：poll The way

·  Mother works in the room , The child wakes up by himself , Go out of the room and tell mom ： Asynchronous notification

Back 3 Both ways require children to interrupt their mothers ： Interrupt her sleep 、 Her job .

In fact, it can “ interrupt ” Mom has a lot to do

·  Distant cat calls ： Ignore

·  Doorbell , The child cries ： Corresponding to different treatments

·  Under the weather ： Get some rest

·  A spider fell down ： Run away

Mother is reading . The interrupted process ：

·  I'm reading a book

·  All kinds of sounds occur ： Interrupt source

o  Distant cat calls

o  The child cries

o  Doorbell ...

How to deal with

·  Put a bookmark in the book first , close the book ： Save the scene

·  To deal with ： Interrupt service routine

·  Come back and continue reading ： Return processing

Interrupt in embedded system

CPU In the process of operation, it will be affected by various “ abnormal ” interrupt ：

·  Undefined

·  Instructions 、 There's a problem with the data

· SWI： Soft interrupt

·  Break it up

·  interrupt

An interrupt is also an exception . There are many things that cause interruptions ：

·  Key

·  Timer

· ADC convert network

· UART After sending data 、 Receive the data

·  wait

These interrupt sources , To the interrupt controller , The interrupt controller selects the highest interrupt and notifies CPU

Interrupt processing flow

·  initialization ：

o  Set interrupt source ： What kind of interruption

o  Set interrupt controller （ Mask an interrupt , Interrupt priority ）

o  Set up CPU Main switch ： To interrupt

·  Perform normal procedures ：

·  The interrupt ： For example, press the button -> Interrupt controller -> CPU

· CPU If a command is not executed, it will be checked for interruption / The generation of anomalies

· CPU There was an interruption / abnormal , Start to deal with ：

o  For different exceptions , Jump to a different address to execute the program

o  On this address , It's just a jump command , Jump to execute a function , This is the exception vector .

after 3 All the steps are done by hardware . The software does ：

·  Save the scene （ Various registers ）

·  Handling exceptions and interrupts

·  Restore the scene