[AUTOSAR eight OS]

1 Tasks

• Basic tasks （Basic Task）
• Extended tasks （Extended Task）

1.1 Basic tasks （Basic Task）

When the operating system is started , be-all Task All enter the suspended state ; Then from The user triggers what needs to be executed Task（ Generally in DaVinci There are configurations in , Can generate code , For example, it is configured to initialize execution or 100ms Cycle execution ）; Triggered Task Are directly ready , Waiting to be OS call ; At this time OS Will be based on Task Priority to schedule Task（ If there is a high priority Task Ready ,OS Will suspend the ongoing Task, Give priority to high priority Task perform , Then continue to execute the suspended Task, Similar to interrupt nesting ）.

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1.2 Extended tasks （Extended Task）

The extended task has one more waiting state than the basic task , This state is when Task While running , Suddenly need an event （ Like just ADC Data update ）, While waiting for this event ,Task Enter the waiting state and release CPU resources , Low priority Task You can continue to occupy CPU; When ADC The data update event is coming , Then let's wait Task Enter ready state , Because of the high priority , Then enter the running state .

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2 Alarms

Alarms As the name suggests, it is an alarm clock , Role is Set a cycle timing , But it can not only be used to trigger Task, It can also be used to set a Event Events or Call A callback function .
Alarms The time benchmark of is generated by hardware timer Tick Time Decisive , Every Tick Time How much time can I spend in DaVinci Middle configuration . Every one of them Tick Time,System Counter Benga 1, Add to the preset value ,Alarm It was triggered .

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3 Interrupts

• Interrupt priority is always higher than Task
• In the priority of interrupts, class I interrupts are greater than class II interrupts ;
• periodic Task And periodic interrupts can be processed periodically , But in the case of strict cycle requirements , It is better to use interrupt

3.1 Class I interrupt （Cat1）

• No access OS service , After the interruption, return directly to the interruption
• here OS Still follow the normal schedule

3.2 Class II interrupt （Cat2）

• Will visit some OS service （ some OS Service is not allowed , such as TerminateTask）
• Once after the interruption OS The rescheduling of .

3.3 The difference between class I and class II interrupts

• Class I interrupt ： Because... Is not allowed OS service , Therefore, you cannot call Task2 Trigger function , You can only return to after exiting the interrupt Task1, And then wait OS Should be called Task2 I'll call it again when
• Class II interrupt ： Because it is allowed to use OS Some services , At this time, we write Task2 Trigger function , Then a scheduling will occur directly when the interrupt ends and returns , because Task2 Triggered , High priority , Then go straight into Task2 function , etc. Task2 End of run , Back again Task1 Continue operation （ The following figure 2 situation ）; Of course , It is also possible not to trigger other Task,OS The scheduling will still return to Task1 In the middle （ The following figure 1 situation ）
  

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4 IOC (Inter OS Application Communicator)

It opens a protected in memory IOC Area , For cross nuclear communication .
This area supports multiple input multiple output , from OS management , stay DaVinci Generally, it is generated automatically without modification , This is for understanding only

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5 OS Resources

When at least two Task When accessing the same resource in parallel , There's probably something wrong with it ,OS Resources It is used to prevent parallel access errors

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