中断管理控制器NVIC与stm32中断使用
什么是NVIC?即嵌套向量中断控制器(Nested Vectored Interrupt Controller)。它是属于Cortex内核的器件，是非常强大与方便的嵌套向量中断控制器，不可屏蔽中断 (NMI)和外部中断都由它来处理，而SYSTICK不是由NVIC来控制的。
NVIC 特性
嵌套向量中断控制器 NVIC 包含以下特性：
● STM32F405xx/07xx 和 STM32F415xx/17xx 具有 82 个可屏蔽中断通道， STM32F42xxx
和 STM32F43xxx 具有多达 86 个可屏蔽中断通道（不包括 Cortex™-M4F 的 16 根中
断线）
● 16 个可编程优先级（stm32F4只使用了 4 位中断优先级）
● 低延迟异常和中断处理
● 电源管理控制
● 系统控制寄存器的实现
嵌套向量中断控制器 (NVIC) 和处理器内核接口紧密配合，可以实现低延迟的中断处理和晚
到中断的高效处理。
包括内核异常在内的所有中断均通过 NVIC 进行管理。更多关于异常和 NVIC 编程的说明，
请参考《 ARM Cortex™-M4F 技术参考手册》中的第 5 章：异常和第 8 章：嵌套向量中断控
制器。
通过阅读《STM32xxx参考手册》中“中断与事件”一章我们可以知道ST公司生产的stm32芯片对cotex内核的嵌套向量中断控制器 NVIC 的使用进行了一些小的改动，
改动一：减少了用于设置优先级的比特位。stm32只用了4个比特位来表示中断的优先级
1.中断优先级分组
Cortex-M3中有两个优先级的概念--抢占式优先级和响应优先级，有人把响应优先级称作'亚优先级'或'副优先级'，每个中断源都需要被指定
这两种优先级。
具有高抢占式优先级的中断可以在具有低抢占式优先级的中断处理过程中被响应，即中断嵌套，或者说高抢占式优先级的中断可以嵌套在
低抢占式优先级的中断中。
当两个中断源的抢占式优先级相同时，这两个中断将没有嵌套关系，当一个中断到来后，如果正在处理另一个中断，这个后到来的中断就要等到
前一个中断处理完之后才能被处理。如果这两个中断同时到达，则中断控制器根据他们的响应优先级高低来决定先处理哪一个；如果他们的抢占
优先级和响应优先级都相等，则根据他们在中断表中的排位顺序决定先处理哪一个。
Cortex内核具有强大的异常响应系统，它把能够打断当前代码执行流程的事件分为异常(exception)和中断(interrupt)，并把它们用一个表
管理起来，编号为0~15的称为内核异常，而16以上的则称为外部中断这个表就称为中断向量表。
正是因为每个中断源都需要被指定这两种优先级，就需要有相应的寄存器位记录每个中断的优先级；在Cortex-M3中定义了8个比特位用于设置
中断源的优先级，这8个比特位可以有8种分配方式，如下：
1. 所有8位用于指定响应优先级
2. 最高1位用于指定抢占式优先级，最低7位用于指定响应优先级
3. 最高2位用于指定抢占式优先级，最低6位用于指定响应优先级
4. 最高3位用于指定抢占式优先级，最低5位用于指定响应优先级
5. 最高4位用于指定抢占式优先级，最低4位用于指定响应优先级
6. 最高5位用于指定抢占式优先级，最低3位用于指定响应优先级
7. 最高6位用于指定抢占式优先级，最低2位用于指定响应优先级
8. 最高7位用于指定抢占式优先级，最低1位用于指定响应优先级
以上便是优先级分组的概念，但是Cortex-M3允许具有较少中断源时使用较少的寄存器位指定中断源的优先级。
而 STM32对这个表重新进行了编排，把编号从-3至6的中断向量定义为系统异常，编号为负的内核异常不能被设置优先级，如复位(Reset)、
不可屏蔽中断 (NMI)、硬错误(Hardfault)。从编号 7开始的为外部中断，这些中断的优先级都是可以用户更改的。详细的 STM32中断向量号
可以在startup_stm32f10x_XX.s中查找。
因此STM32把指定中断优先级的寄存器位减少到4位，这4个寄存器位的分组方式如下：
第0组：所有4位用于指定响应优先级（16种）
第1组：最高1位用于指定抢占式优先级，最低3位用于指定响应优先级(8种)
第2组：最高2位用于指定抢占式优先级，最低2位用于指定响应优先级(4种)
第3组：最高3位用于指定抢占式优先级，最低1位用于指定响应优先级(2种)
第4组：所有4位用于指定抢占式优先级
改动二：stm32增加了外部中断/事件控制器 (EXTI)
EXTI 主要特性
EXTI 控制器的主要特性如下：
● 每个中断/事件线上都具有独立的触发和屏蔽
● 每个中断线都具有专用的状态位
● 支持多达 23 个软件事件/中断请求
● 检测脉冲宽度低于 APB2 时钟宽度的外部信号。有关此参数的详细信息，请参见
STM32F4xx 数据手册的电气特性部分。
多达 140 个 GPIO（ STM32F405xx/07xx 和 STM32F415xx/17xx）通过以下方式连接到 16 个 外部中断/事件线：
● EXTI 线 16 连接到 PVD 输出
● EXTI 线 17 连接到 RTC 闹钟事件
● EXTI 线 18 连接到 USB OTG FS 唤醒事件
● EXTI 线 19 连接到以太网唤醒事件
● EXTI 线 20 连接到 USB OTG HS（在 FS 中配置）唤醒事件
● EXTI 线 21 连接到 RTC 入侵和时间戳事件
● EXTI 线 22 连接到 RTC 唤醒事件
/**
* @brief Configuration of the Cortex-M4 Processor and Core Peripherals
*/
#define __CM4_REV 0x0001 /*!< Core revision r0p1 */
#define __MPU_PRESENT 1 /*!< STM32F4XX provides an MPU */
#define __NVIC_PRIO_BITS 4 /*!< STM32F4XX uses 4 Bits for the Priority Levels */
#define __Vendor_SysTickConfig 0 /*!< Set to 1 if different SysTick Config is used */
#define __FPU_PRESENT 1 /*!< FPU present */
/**
* @brief STM32F4XX Interrupt Number Definition, according to the selected device
* in @ref Library_configuration_section
*/
typedef enum IRQn
{
/****** Cortex-M4 Processor Exceptions Numbers ****************************************************************/
NonMaskableInt_IRQn = -14, /*!< 2 Non Maskable Interrupt */
MemoryManagement_IRQn = -12, /*!< 4 Cortex-M4 Memory Management Interrupt */
BusFault_IRQn = -11, /*!< 5 Cortex-M4 Bus Fault Interrupt */
UsageFault_IRQn = -10, /*!< 6 Cortex-M4 Usage Fault Interrupt */
SVCall_IRQn = -5, /*!< 11 Cortex-M4 SV Call Interrupt */
DebugMonitor_IRQn = -4, /*!< 12 Cortex-M4 Debug Monitor Interrupt */
PendSV_IRQn = -2, /*!< 14 Cortex-M4 Pend SV Interrupt */
SysTick_IRQn = -1, /*!< 15 Cortex-M4 System Tick Interrupt */
/****** STM32 specific Interrupt Numbers **********************************************************************/
WWDG_IRQn = 0, /*!< Window WatchDog Interrupt */
PVD_IRQn = 1, /*!< PVD through EXTI Line detection Interrupt */
TAMP_STAMP_IRQn = 2, /*!< Tamper and TimeStamp interrupts through the EXTI line */
RTC_WKUP_IRQn = 3, /*!< RTC Wakeup interrupt through the EXTI line */
FLASH_IRQn = 4, /*!< FLASH global Interrupt */
RCC_IRQn = 5, /*!< RCC global Interrupt */
EXTI0_IRQn = 6, /*!< EXTI Line0 Interrupt */
EXTI1_IRQn = 7, /*!< EXTI Line1 Interrupt */
EXTI2_IRQn = 8, /*!< EXTI Line2 Interrupt */
EXTI3_IRQn = 9, /*!< EXTI Line3 Interrupt */
EXTI4_IRQn = 10, /*!< EXTI Line4 Interrupt */
DMA1_Stream0_IRQn = 11, /*!< DMA1 Stream 0 global Interrupt */
DMA1_Stream1_IRQn = 12, /*!< DMA1 Stream 1 global Interrupt */
DMA1_Stream2_IRQn = 13, /*!< DMA1 Stream 2 global Interrupt */
DMA1_Stream3_IRQn = 14, /*!< DMA1 Stream 3 global Interrupt */
DMA1_Stream4_IRQn = 15, /*!< DMA1 Stream 4 global Interrupt */
DMA1_Stream5_IRQn = 16, /*!< DMA1 Stream 5 global Interrupt */
DMA1_Stream6_IRQn = 17, /*!< DMA1 Stream 6 global Interrupt */
ADC_IRQn = 18, /*!< ADC1, ADC2 and ADC3 global Interrupts */
#if defined (STM32F40_41xxx)
CAN1_TX_IRQn = 19, /*!< CAN1 TX Interrupt */
CAN1_RX0_IRQn = 20, /*!< CAN1 RX0 Interrupt */
CAN1_RX1_IRQn = 21, /*!< CAN1 RX1 Interrupt */
CAN1_SCE_IRQn = 22, /*!< CAN1 SCE Interrupt */
EXTI9_5_IRQn = 23, /*!< External Line[9:5] Interrupts */
TIM1_BRK_TIM9_IRQn = 24, /*!< TIM1 Break interrupt and TIM9 global interrupt */
TIM1_UP_TIM10_IRQn = 25, /*!< TIM1 Update Interrupt and TIM10 global interrupt */
TIM1_TRG_COM_TIM11_IRQn = 26, /*!< TIM1 Trigger and Commutation Interrupt and TIM11 global interrupt */
TIM1_CC_IRQn = 27, /*!< TIM1 Capture Compare Interrupt */
TIM2_IRQn = 28, /*!< TIM2 global Interrupt */
TIM3_IRQn = 29, /*!< TIM3 global Interrupt */
TIM4_IRQn = 30, /*!< TIM4 global Interrupt */
I2C1_EV_IRQn = 31, /*!< I2C1 Event Interrupt */
I2C1_ER_IRQn = 32, /*!< I2C1 Error Interrupt */
I2C2_EV_IRQn = 33, /*!< I2C2 Event Interrupt */
I2C2_ER_IRQn = 34, /*!< I2C2 Error Interrupt */
SPI1_IRQn = 35, /*!< SPI1 global Interrupt */
SPI2_IRQn = 36, /*!< SPI2 global Interrupt */
USART1_IRQn = 37, /*!< USART1 global Interrupt */
USART2_IRQn = 38, /*!< USART2 global Interrupt */
USART3_IRQn = 39, /*!< USART3 global Interrupt */
EXTI15_10_IRQn = 40, /*!< External Line[15:10] Interrupts */
RTC_Alarm_IRQn = 41, /*!< RTC Alarm (A and B) through EXTI Line Interrupt */
OTG_FS_WKUP_IRQn = 42, /*!< USB OTG FS Wakeup through EXTI line interrupt */
TIM8_BRK_TIM12_IRQn = 43, /*!< TIM8 Break Interrupt and TIM12 global interrupt */
TIM8_UP_TIM13_IRQn = 44, /*!< TIM8 Update Interrupt and TIM13 global interrupt */
TIM8_TRG_COM_TIM14_IRQn = 45, /*!< TIM8 Trigger and Commutation Interrupt and TIM14 global interrupt */
TIM8_CC_IRQn = 46, /*!< TIM8 Capture Compare Interrupt */
DMA1_Stream7_IRQn = 47, /*!< DMA1 Stream7 Interrupt */
FSMC_IRQn = 48, /*!< FSMC global Interrupt */
SDIO_IRQn = 49, /*!< SDIO global Interrupt */
TIM5_IRQn = 50, /*!< TIM5 global Interrupt */
SPI3_IRQn = 51, /*!< SPI3 global Interrupt */
UART4_IRQn = 52, /*!< UART4 global Interrupt */
UART5_IRQn = 53, /*!< UART5 global Interrupt */
TIM6_DAC_IRQn = 54, /*!< TIM6 global and DAC1&2 underrun error interrupts */
TIM7_IRQn = 55, /*!< TIM7 global interrupt */
DMA2_Stream0_IRQn = 56, /*!< DMA2 Stream 0 global Interrupt */
DMA2_Stream1_IRQn = 57, /*!< DMA2 Stream 1 global Interrupt */
DMA2_Stream2_IRQn = 58, /*!< DMA2 Stream 2 global Interrupt */
DMA2_Stream3_IRQn = 59, /*!< DMA2 Stream 3 global Interrupt */
DMA2_Stream4_IRQn = 60, /*!< DMA2 Stream 4 global Interrupt */
ETH_IRQn = 61, /*!< Ethernet global Interrupt */
ETH_WKUP_IRQn = 62, /*!< Ethernet Wakeup through EXTI line Interrupt */
CAN2_TX_IRQn = 63, /*!< CAN2 TX Interrupt */
CAN2_RX0_IRQn = 64, /*!< CAN2 RX0 Interrupt */
CAN2_RX1_IRQn = 65, /*!< CAN2 RX1 Interrupt */
CAN2_SCE_IRQn = 66, /*!< CAN2 SCE Interrupt */
OTG_FS_IRQn = 67, /*!< USB OTG FS global Interrupt */
DMA2_Stream5_IRQn = 68, /*!< DMA2 Stream 5 global interrupt */
DMA2_Stream6_IRQn = 69, /*!< DMA2 Stream 6 global interrupt */
DMA2_Stream7_IRQn = 70, /*!< DMA2 Stream 7 global interrupt */
USART6_IRQn = 71, /*!< USART6 global interrupt */
I2C3_EV_IRQn = 72, /*!< I2C3 event interrupt */
I2C3_ER_IRQn = 73, /*!< I2C3 error interrupt */
OTG_HS_EP1_OUT_IRQn = 74, /*!< USB OTG HS End Point 1 Out global interrupt */
OTG_HS_EP1_IN_IRQn = 75, /*!< USB OTG HS End Point 1 In global interrupt */
OTG_HS_WKUP_IRQn = 76, /*!< USB OTG HS Wakeup through EXTI interrupt */
OTG_HS_IRQn = 77, /*!< USB OTG HS global interrupt */
DCMI_IRQn = 78, /*!< DCMI global interrupt */
CRYP_IRQn = 79, /*!< CRYP crypto global interrupt */
HASH_RNG_IRQn = 80, /*!< Hash and Rng global interrupt */
FPU_IRQn = 81 /*!< FPU global interrupt */
#endif /* STM32F40_41xxx */
} IRQn_Type;
NVIC控制器用于管理系统所使用的优先级分组，以及每个中断通道的抢占优先级与相应优先级，是否使能中断，等。
EXTI控制器用于管理与配置每个EXTI中断的使能 响应方式，等。
接下来我们配合函数来分析stm32中断的配置与使用方法
要使用stm32中断
第一步：必须使用函数NVIC_PriorityGroupConfig(uint32_t NVIC_PriorityGroup)I配置系统所使用的优先级分组
/**
* @brief Configures the priority grouping: pre-emption priority and subpriority.
* @param NVIC_PriorityGroup: specifies the priority grouping bits length.
* This parameter can be one of the following values:
* @arg NVIC_PriorityGroup_0: 0 bits for pre-emption priority
* 4 bits for subpriority
* @arg NVIC_PriorityGroup_1: 1 bits for pre-emption priority
* 3 bits for subpriority
* @arg NVIC_PriorityGroup_2: 2 bits for pre-emption priority
* 2 bits for subpriority
* @arg NVIC_PriorityGroup_3: 3 bits for pre-emption priority
* 1 bits for subpriority
* @arg NVIC_PriorityGroup_4: 4 bits for pre-emption priority
* 0 bits for subpriority
* @note When the NVIC_PriorityGroup_0 is selected, IRQ pre-emption is no more possible.
* The pending IRQ priority will be managed only by the subpriority.
* @retval None
*/
void NVIC_PriorityGroupConfig(uint32_t NVIC_PriorityGroup)
{
/* Check the parameters */
assert_param(IS_NVIC_PRIORITY_GROUP(NVIC_PriorityGroup));
/* Set the PRIGROUP[10:8] bits according to NVIC_PriorityGroup value */
SCB->AIRCR = AIRCR_VECTKEY_MASK | NVIC_PriorityGroup;
}
第二步：必须使用函数NVIC_Init（）配置所使用通道的优先级并使能该通道
/**
* @brief Initializes the NVIC peripheral according to the specified
* parameters in the NVIC_InitStruct.
* @note To configure interrupts priority correctly, the NVIC_PriorityGroupConfig()
* function should be called before.
* @param NVIC_InitStruct: pointer to a NVIC_InitTypeDef structure that contains
* the configuration information for the specified NVIC peripheral.
* @retval None
*/
void NVIC_Init(NVIC_InitTypeDef* NVIC_InitStruct)
{
uint8_t tmppriority = 0x00, tmppre = 0x00, tmpsub = 0x0F;
/* Check the parameters */
assert_param(IS_FUNCTIONAL_STATE(NVIC_InitStruct->NVIC_IRQChannelCmd));
assert_param(IS_NVIC_PREEMPTION_PRIORITY(NVIC_InitStruct->NVIC_IRQChannelPreemptionPriority));
assert_param(IS_NVIC_SUB_PRIORITY(NVIC_InitStruct->NVIC_IRQChannelSubPriority));
if (NVIC_InitStruct->NVIC_IRQChannelCmd != DISABLE)
{
/* Compute the Corresponding IRQ Priority --------------------------------*/
tmppriority = (0x700 - ((SCB->AIRCR) & (uint32_t)0x700))>> 0x08;
tmppre = (0x4 - tmppriority);
tmpsub = tmpsub >> tmppriority;
tmppriority = NVIC_InitStruct->NVIC_IRQChannelPreemptionPriority << tmppre;
tmppriority |= (uint8_t)(NVIC_InitStruct->NVIC_IRQChannelSubPriority & tmpsub);
tmppriority = tmppriority << 0x04;
NVIC->IP[NVIC_InitStruct->NVIC_IRQChannel] = tmppriority;
/* Enable the Selected IRQ Channels --------------------------------------*/
NVIC->ISER[NVIC_InitStruct->NVIC_IRQChannel >> 0x05] =
(uint32_t)0x01 << (NVIC_InitStruct->NVIC_IRQChannel & (uint8_t)0x1F);
}
else
{
/* Disable the Selected IRQ Channels -------------------------------------*/
NVIC->ICER[NVIC_InitStruct->NVIC_IRQChannel >> 0x05] =
(uint32_t)0x01 << (NVIC_InitStruct->NVIC_IRQChannel & (uint8_t)0x1F);
}
}
如果是普通的非EXTI类型中断通过以上两步就可以使用中断了，如果是EXTI类型中断经过以上两步后还不能使用，还要完成以下两步才能使用中断。
第三步：使用函数SYSCFG_EXTILineConfig(uint8_t EXTI_PortSourceGPIOx, uint8_t EXTI_PinSourcex)选择要连接到EXTI中断通道的GPIO
/**
* @brief Selects the GPIO pin used as EXTI Line.
* @param EXTI_PortSourceGPIOx : selects the GPIO port to be used as source for
* EXTI lines where x can be (A..K) for STM32F42xxx/43xxx devices, (A..I)
* for STM32F405xx/407xx and STM32F415xx/417xx devices or (A, B, C, D and H)
* for STM32401xx devices.
*
* @param EXTI_PinSourcex: specifies the EXTI line to be configured.
* This parameter can be EXTI_PinSourcex where x can be (0..15, except
* for EXTI_PortSourceGPIOI x can be (0..11) for STM32F405xx/407xx
* and STM32F405xx/407xx devices and for EXTI_PortSourceGPIOK x can
* be (0..7) for STM32F42xxx/43xxx devices.
*
* @retval None
*/
void SYSCFG_EXTILineConfig(uint8_t EXTI_PortSourceGPIOx, uint8_t EXTI_PinSourcex)
{
uint32_t tmp = 0x00;
/* Check the parameters */
assert_param(IS_EXTI_PORT_SOURCE(EXTI_PortSourceGPIOx));
assert_param(IS_EXTI_PIN_SOURCE(EXTI_PinSourcex));
tmp = ((uint32_t)0x0F) << (0x04 * (EXTI_PinSourcex & (uint8_t)0x03));
SYSCFG->EXTICR[EXTI_PinSourcex >> 0x02] &= ~tmp;
SYSCFG->EXTICR[EXTI_PinSourcex >> 0x02] |= (((uint32_t)EXTI_PortSourceGPIOx) << (0x04 * (EXTI_PinSourcex & (uint8_t)0x03)));
}
第四步：使用函数EXTI_Init(EXTI_InitTypeDef* EXTI_InitStruct)设置所选中断EXTI通道的触发方式，并使能该EXTI通道
/**
* @brief Initializes the EXTI peripheral according to the specified
* parameters in the EXTI_InitStruct.
* @param EXTI_InitStruct: pointer to a EXTI_InitTypeDef structure
* that contains the configuration information for the EXTI peripheral.
* @retval None
*/
void EXTI_Init(EXTI_InitTypeDef* EXTI_InitStruct)
{
uint32_t tmp = 0;
/* Check the parameters */
assert_param(IS_EXTI_MODE(EXTI_InitStruct->EXTI_Mode));
assert_param(IS_EXTI_TRIGGER(EXTI_InitStruct->EXTI_Trigger));
assert_param(IS_EXTI_LINE(EXTI_InitStruct->EXTI_Line));
assert_param(IS_FUNCTIONAL_STATE(EXTI_InitStruct->EXTI_LineCmd));
tmp = (uint32_t)EXTI_BASE;
if (EXTI_InitStruct->EXTI_LineCmd != DISABLE)
{
/* Clear EXTI line configuration */
EXTI->IMR &= ~EXTI_InitStruct->EXTI_Line;
EXTI->EMR &= ~EXTI_InitStruct->EXTI_Line;
tmp += EXTI_InitStruct->EXTI_Mode;
*(__IO uint32_t *) tmp |= EXTI_InitStruct->EXTI_Line;
/* Clear Rising Falling edge configuration */
EXTI->RTSR &= ~EXTI_InitStruct->EXTI_Line;
EXTI->FTSR &= ~EXTI_InitStruct->EXTI_Line;
/* Select the trigger for the selected external interrupts */
if (EXTI_InitStruct->EXTI_Trigger == EXTI_Trigger_Rising_Falling)
{
/* Rising Falling edge */
EXTI->RTSR |= EXTI_InitStruct->EXTI_Line;
EXTI->FTSR |= EXTI_InitStruct->EXTI_Line;
}
else
{
tmp = (uint32_t)EXTI_BASE;
tmp += EXTI_InitStruct->EXTI_Trigger;
*(__IO uint32_t *) tmp |= EXTI_InitStruct->EXTI_Line;
}
}
else
{
tmp += EXTI_InitStruct->EXTI_Mode;
/* Disable the selected external lines */
*(__IO uint32_t *) tmp &= ~EXTI_InitStruct->EXTI_Line;
}
}
以上大概讲解了一下NVIC的概念与stm32中断的使用方法，就是这次学习的笔记了