问题1
工作需要出bug的芯片不详细说明，该芯片的CPU含有32个中断源，一般来说，以stm32为例，中断向量表定义在startup_stm32f40_41xxx.s中，写为：
; Vector Table Mapped to Address 0 at Reset
AREA RESET, DATA, READONLY
EXPORT __Vectors
EXPORT __Vectors_End
EXPORT __Vectors_Size
__Vectors DCD __initial_sp ; Top of Stack
DCD Reset_Handler ; Reset Handler
DCD NMI_Handler ; NMI Handler
DCD HardFault_Handler ; Hard Fault Handler
DCD MemManage_Handler ; MPU Fault Handler
DCD BusFault_Handler ; Bus Fault Handler
DCD UsageFault_Handler ; Usage Fault Handler
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD 0 ; Reserved
DCD SVC_Handler ; SVCall Handler
DCD DebugMon_Handler ; Debug Monitor Handler
DCD 0 ; Reserved
DCD PendSV_Handler ; PendSV Handler
DCD SysTick_Handler ; SysTick Handler
; External Interrupts
DCD WWDG_IRQHandler ; Window WatchDog
DCD PVD_IRQHandler ; PVD through EXTI Line detection
DCD TAMP_STAMP_IRQHandler ; Tamper and TimeStamps through the EXTI line
DCD RTC_WKUP_IRQHandler ; RTC Wakeup through the EXTI line
DCD FLASH_IRQHandler ; FLASH
DCD RCC_IRQHandler ; RCC
DCD EXTI0_IRQHandler ; EXTI Line0
DCD EXTI1_IRQHandler ; EXTI Line1
DCD EXTI2_IRQHandler ; EXTI Line2
DCD EXTI3_IRQHandler ; EXTI Line3
DCD EXTI4_IRQHandler ; EXTI Line4
DCD DMA1_Stream0_IRQHandler ; DMA1 Stream 0
DCD DMA1_Stream1_IRQHandler ; DMA1 Stream 1
DCD DMA1_Stream2_IRQHandler ; DMA1 Stream 2
DCD DMA1_Stream3_IRQHandler ; DMA1 Stream 3
DCD DMA1_Stream4_IRQHandler ; DMA1 Stream 4
DCD DMA1_Stream5_IRQHandler ; DMA1 Stream 5
DCD DMA1_Stream6_IRQHandler ; DMA1 Stream 6
DCD ADC_IRQHandler ; ADC1, ADC2 and ADC3s
DCD CAN1_TX_IRQHandler ; CAN1 TX
DCD CAN1_RX0_IRQHandler ; CAN1 RX0
DCD CAN1_RX1_IRQHandler ; CAN1 RX1
DCD CAN1_SCE_IRQHandler ; CAN1 SCE
DCD EXTI9_5_IRQHandler ; External Line[9:5]s
DCD TIM1_BRK_TIM9_IRQHandler ; TIM1 Break and TIM9
DCD TIM1_UP_TIM10_IRQHandler ; TIM1 Update and TIM10
DCD TIM1_TRG_COM_TIM11_IRQHandler ; TIM1 Trigger and Commutation and TIM11
DCD TIM1_CC_IRQHandler ; TIM1 Capture Compare
DCD TIM2_IRQHandler ; TIM2
DCD TIM3_IRQHandler ; TIM3
DCD TIM4_IRQHandler ; TIM4
DCD I2C1_EV_IRQHandler ; I2C1 Event
DCD I2C1_ER_IRQHandler ; I2C1 Error
DCD I2C2_EV_IRQHandler ; I2C2 Event
DCD I2C2_ER_IRQHandler ; I2C2 Error
DCD SPI1_IRQHandler ; SPI1
DCD SPI2_IRQHandler ; SPI2
DCD USART1_IRQHandler ; USART1
DCD USART2_IRQHandler ; USART2
DCD USART3_IRQHandler ; USART3
DCD EXTI15_10_IRQHandler ; External Line[15:10]s
DCD RTC_Alarm_IRQHandler ; RTC Alarm (A and B) through EXTI Line
DCD OTG_FS_WKUP_IRQHandler ; USB OTG FS Wakeup through EXTI line
DCD TIM8_BRK_TIM12_IRQHandler ; TIM8 Break and TIM12
DCD TIM8_UP_TIM13_IRQHandler ; TIM8 Update and TIM13
DCD TIM8_TRG_COM_TIM14_IRQHandler ; TIM8 Trigger and Commutation and TIM14
DCD TIM8_CC_IRQHandler ; TIM8 Capture Compare
DCD DMA1_Stream7_IRQHandler ; DMA1 Stream7
DCD FSMC_IRQHandler ; FSMC
DCD SDIO_IRQHandler ; SDIO
DCD TIM5_IRQHandler ; TIM5
DCD SPI3_IRQHandler ; SPI3
DCD UART4_IRQHandler ; UART4
DCD UART5_IRQHandler ; UART5
DCD TIM6_DAC_IRQHandler ; TIM6 and DAC1&2 underrun errors
DCD TIM7_IRQHandler ; TIM7
DCD DMA2_Stream0_IRQHandler ; DMA2 Stream 0
DCD DMA2_Stream1_IRQHandler ; DMA2 Stream 1
DCD DMA2_Stream2_IRQHandler ; DMA2 Stream 2
DCD DMA2_Stream3_IRQHandler ; DMA2 Stream 3
DCD DMA2_Stream4_IRQHandler ; DMA2 Stream 4
DCD ETH_IRQHandler ; Ethernet
DCD ETH_WKUP_IRQHandler ; Ethernet Wakeup through EXTI line
DCD CAN2_TX_IRQHandler ; CAN2 TX
DCD CAN2_RX0_IRQHandler ; CAN2 RX0
DCD CAN2_RX1_IRQHandler ; CAN2 RX1
DCD CAN2_SCE_IRQHandler ; CAN2 SCE
DCD OTG_FS_IRQHandler ; USB OTG FS
DCD DMA2_Stream5_IRQHandler ; DMA2 Stream 5
DCD DMA2_Stream6_IRQHandler ; DMA2 Stream 6
DCD DMA2_Stream7_IRQHandler ; DMA2 Stream 7
DCD USART6_IRQHandler ; USART6
DCD I2C3_EV_IRQHandler ; I2C3 event
DCD I2C3_ER_IRQHandler ; I2C3 error
DCD OTG_HS_EP1_OUT_IRQHandler ; USB OTG HS End Point 1 Out
DCD OTG_HS_EP1_IN_IRQHandler ; USB OTG HS End Point 1 In
DCD OTG_HS_WKUP_IRQHandler ; USB OTG HS Wakeup through EXTI
DCD OTG_HS_IRQHandler ; USB OTG HS
DCD DCMI_IRQHandler ; DCMI
DCD CRYP_IRQHandler ; CRYP crypto
DCD HASH_RNG_IRQHandler ; Hash and Rng
DCD FPU_IRQHandler ; FPU
__Vectors_End
__Vectors_Size EQU __Vectors_End - __Vectors
AREA |.text|, CODE, READONLY其中的XX_Handler为中断服务函数，对中断服务函数进行实现后即可使用，我们开发芯片程序时常用的一种设计思路是这样的：
- 主程序中定义一个全局变量
flag用于记录是否有外部输入需要处理，打开中断，执行后台任务并检测输入flag - 进入中断后关闭中断并执行中断服务函数
- 中断服务函数中对
flag进行赋值，标记触发来源 - 中断服务函数打开中断，退出
- 主程序检测到输入
flag，执行相关高优先级任务后，继续执行后台任务，等待下一次外部输入
按照上面的设计思路，假设我们以TIM3_IRQHandler中断为例，在主函数中这样实现：
unsigned int flag = 0;
int main(void)
{
flag = 0
while(flag==0)
{
;
}
//do something for IRQ
}在中断服务函数中对flag进行修改表示触发了中断：
void TIM3_IRQHandler(void)
{
flag = 1;
TIM_ClearITPendingBit(TIM3, TIM_IT_Update); //清除中断标志位
}运行程序后的结果是这样（举例说明）：程序在进入中断服务函数后对flag进行置位并返回但是并未退出while循环，即flag的修改没有起作用。
这里最直接的原因是在汇编程序中比较的两个寄存器的值并未修改，即C代码在编译后对结果进行了优化，参考：周立功著 软件单元测试入门与实践 23页：
因此最直接的办法是用volatile关键字对变量进行修饰，当然也有其他办法，出现问题的直接因素在于flag=0和while(flag==0)被编译器直接优化掉了，这里可以写一个伪函数对flag进行一个操作绕开编译器的优化判断，但是增加了额外的开销，并不合适：
flag = 0;
fake_func(&flag);
while(flag==0);
//do something问题2
中断是由通信单元产生的，在解决了中断无响应的问题后出现了上电复位后打印输出不稳定的现象，且发生次数和时间不固定。由于数据是在配置时钟后发出，中间无其他操作，初步认为是配置时钟造成的原因，芯片采用内部时钟，因此增加约10ms延时后输出稳定不再发生乱码，原因应该是PLL需要锁定时间，因此不能在配置PLL后直接执行与时序有关的操作。
原文地址：https://www.cnblogs.com/RegressionWorldLine/p/11729674.html
时间： 2024-08-29 22:55:19