STM32之NVIC理解

1、则SPIl_IRQChannel的抢占优先级高，EXTIO_IRQChannel做事的时候可以打断（嵌套）STM32有43个channel的settable的中断源；AIRC(ApplicationInterruptandResetRegister)寄存器中有用于指定优先级的4bits。这4个bits用于分配preemption优先级和sub优先级，在STM32的固件库中定义如下#defineNVIC_PriorityGroup_0(u32)0 x700)#defineNVIC_PriorityGroup_1(u32)0 x600)#defineNVIC_PriorityGroup_2(u32

2、)0 x500)#defineNVIC_PriorityGroup_3(u32)0 x400)#defineNVIC_PriorityGroup_4(u32)0 x300)每个工程只能有一种分组方式：1个，子优先级为16个；2个，子优先级为8个；4个，子优先级为4个；8个，子优先级为2个；16个，子优先级为1个；按NVIC_PriorityGroup_0来分组：抢占优先级为按NVIC_PriorityGroup_l来分组：抢占优先级为按NVIC_PriorityGroup_2来分组：抢占优先级为按NVIC_PriorityGroup_3来分组：抢占优先级为按NVIC_PriorityGroup

3、_0来分组：抢占优先级为抢占优先级高的中断可以打断抢占优先级低的中断；抢占优先级相同时比较响应优先级(子优先级)。先设定分组方式例：NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);/按NVIC_PriorityGroup_4来分组此时，有一中断EXTIO_IRQChannel，你指定他为抢占优先级8,则NVIC_InitStructure.NVIC_IRQChannel=EXTI0_IRQChannel;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=8;/指定抢占式优先级别，可取0-15又

4、有1中断SPIl_IRQChannel，设定如下NVIC_InitStructure.NVIC_IRQChannel=SPI1_IRQChannel;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;/指定抢占式优先级别，可取0-15则SPIl_IRQChannel的抢占优先级高，EXTIO_IRQChannel做事的时候可以打断（嵌套）0-10-10-1又：若分组方式为：NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);/按NVIC_PriorityGroup_3来分组此时就有8个抢占优先

5、级，2个子优先级；EXTIO_IRQChannel中断，你指定他为抢占优先级3,则：NVIC_InitStructure.NVIC_IRQChannel=EXTI0_IRQChannel;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;/指定抢占式优先级别，可取0-7还需要指定他的阶层：NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;/指定响应优先级别，可取又有TIM2_IRQn中断，设定如下：NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;N

6、VIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;/指定抢占式优先级别，可取0-7NVIC_InitStructure.NVIC_IRQChannelSubPriority=3;/指定响应优先级别，可取由于抢占优先级相同，响应优先级EXTIO_IRQChannel中断高于TIM2_IRQn中断，所以EXTIO_IRQChannel可以打断TIM2_IRQn；还有一USB_LP_CANl_RXO_IRQn，设定如下：NVIC_InitStrueture.NVIC_IRQChannel=USB_LP_CANl_RXO_IRQn;/CAN1R

7、XO中断NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;/抢占优先级0NVIC_InitStrueture.NVIC_IRQChannelSubPriority=0;/响应优先级别0，可取USB_LP_CANl_RXO_IRQn优先级最高，前两中断发生时，它都可以打断。附：voidNVIC_Config(void)NVIC_InitTypeDefNVIC_InitStructure;NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3);一个工程中只能使用一种分组方式NVIC_InitStruc

8、ture.NVIC_IRQChannel=USB_LP_CAN1_RX0_IRQn;CAN1RXO中断NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;/抢占优先级0NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;/子优先级为0NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;NVIC_InitSt

9、ructure.NVIC_IRQChannelPreemptionPriority=2;/指定抢占式优先级别，可取0-7NVIC_InitStructure.NVIC_IRQChannelSubPriority=3;/指定响应优先级别，可取0-1NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;NVIC_Init(&NVIC_InitStructure);NVIC_InitStructure.NVIC_IRQChannel=EXTI0_IRQChannel;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=2;/指定抢占式优先级别，可