TIM2 溢出不会触发 TIM2_IRQHandler @ STM32G031J6

Posted 2023-02-19

【中文标题】TIM2 溢出不会触发 TIM2_IRQHandler @ STM32G031J6

【英文标题】：TIM2 overflow does not trigger TIM2_IRQHandler @ STM32G031J6

【发布时间】：2021-12-02 00:07:14

【问题描述】：

通过以下代码，我想让 STM32G031J6M6 的引脚 5 (PA11) 以 50 kHz 闪烁。为此，我将 TIM2 配置为每 10 us 溢出一次。这是调用一个切换 PA11 电平的 ISR（“TIM2_IRGHandler”）。 现在一切正常：切换正常工作，TIM2 计数为 10，重置并再次开始计数。 现在的问题是，当 TIM2 溢出时，我的 ISR 没有被调用。相反，程序只是“崩溃”。我猜它会在 TIM2 溢出时进入一些“默认处理程序”。

（代码编译为 C 代码，不是 C++。）

#include <stdlib.h>

#include <stm32g031xx.h>

/*!
 * \brief Configures pin 5 ("PA11") as digital output.
 */
void config_output(void) 
  RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
  GPIOA->MODER &= ~(0x3u << (11 * 2));
  GPIOA->MODER |= (0x1u << (11 * 2));
  GPIOA->OTYPER &= ~(0x1u << (11 * 1));


/*!
 * \brief Configures TIM2 overflow with 10 us period (-> 100 kHz).
 */
void config_blink_timer(void) 
  //Enable the TIM2 clock.
  RCC->APBENR1 |= RCC_APBENR1_TIM2EN;

  //Make sure the timer's "counter" is off.
  TIM2->CR1 &= ~TIM_CR1_CEN;

  //Reset the peripheral.
  RCC->APBRSTR1 |= (RCC_APBRSTR1_TIM2RST);
  RCC->APBRSTR1 &= ~(RCC_APBRSTR1_TIM2RST);

  //Set the timer prescaler/autoreload timing registers.
  TIM2->PSC = 16 - 1; //-> 16 MHz / 16 = 1 MHz
  TIM2->ARR = 10 - 1; //-> 1/1 MHz * 10 = 10 us (100 kHz)

  //Send an update event to reset the timer and apply settings.
  TIM2->EGR |= TIM_EGR_UG;

  //Enable TIM2 interrupts.
  NVIC_EnableIRQ(TIM2_IRQn);


/*!
 * \brief Enables the "Cycle Timer", which will now fire interrupts that trigger
 * execution of the "App Loop" (--> \c TIM2_IRQHandler()).
 */
void run_app(void) 
  //Clear TIM2_IRQn update interrupt,
  TIM2->SR &= ~TIM_SR_UIF;

  //Enable the hardware interrupt.
  TIM2->DIER |= TIM_DIER_UIE;

  //Enable the timer.
  TIM2->CR1 |= TIM_CR1_CEN;


/*!
 * \brief Initializes any peripheral being used.
 */
void init(void) 
  //Disable interrupts.
  __disable_irq();

  config_output();
  config_blink_timer();

  //Enable interrupts.
  __enable_irq();


/*!
 * \brief Initializes the system and runs the application.
 */
int main(void) 
  init();

  run_app();

  while(1)
    __WFI();

  return EXIT_SUCCESS;


/*!
 * \brief This IRQ handler will be triggered every 10 us by the "Blink Timer".
 * This "time base" is used to blink a LED with a defined pattern (50 kHz,
 * 50% DS).
 */
void TIM2_IRQHandler(void) 
  //Toggle PA11 (pin 5).
  GPIOA->ODR ^= (0x1u << 11);

  //Clear TIM2 update interrupt flag.
  TIM2->SR &= ~TIM_SR_UIF;

  //Power-down until next "tick"/interrupt.
  __WFE();

【问题讨论】：

我不记得这个硬件但是你应该从后台程序中反复调用TIM2->SR &= ~TIM_SR_UIF;吗？这不是你的中断正在寻找的标志吗？

是的，该标志必须由软件清除。它不会自动/由硬件清除。

...但这不是您的 ISR 所基于的标志，因此只能从 ISR 中清除它吗？

@Lundin run_app 不会在循环中调用。

在 IRQ 处理程序中执行 WFE 似乎是一个挂起的秘诀，如果你删除它怎么办？

【参考方案1】：

好的，这个（德国）论坛(-> link to thread) 的人让我走上了正确的道路，最后回答了这个问题：我们可以通过将 TIM2_IRQn 的优先级明确设置为“0”来解决问题。然而，与其治疗症状，不如解决原因，在这种情况下，实际上只能是 SysTick。 但是，我无法再用原始代码重现问题了……如果有人知道这个奇怪现象的答案，当然欢迎。

但现在基本上问题已经解决了。以下代码可以正常工作：

#include <stdlib.h>

#include <stm32g031xx.h>

/*!
 * \brief Configures pin 5 ("PA11") as digital output.
 */
void config_output(void) 
  RCC->IOPENR |= RCC_IOPENR_GPIOAEN;
  GPIOA->MODER &= ~(0x3u << (11 * 2));
  GPIOA->MODER |= (0x1u << (11 * 2));
  GPIOA->OTYPER &= ~(0x1u << (11 * 1));


/*!
 * \brief Configures TIM2 overflow with 10 us period (-> 100 kHz).
 */
void config_blink_timer(void) 
  //Enable the TIM2 clock.
  RCC->APBENR1 |= RCC_APBENR1_TIM2EN;

  //Make sure the timer's "counter" is off.
  TIM2->CR1 &= ~TIM_CR1_CEN;

  //Reset the peripheral.
  RCC->APBRSTR1 |= (RCC_APBRSTR1_TIM2RST);
  RCC->APBRSTR1 &= ~(RCC_APBRSTR1_TIM2RST);

  //Set the timer prescaler/autoreload timing registers.
  TIM2->PSC = 16 - 1; //-> 16 MHz / 16 = 1 MHz
  TIM2->ARR = 10 - 1; //-> 1/1 MHz * 10 = 10 us (100 kHz)

  //Send an update event to reset the timer and apply settings.
  TIM2->EGR |= TIM_EGR_UG;

  //Enable TIM2 interrupts and set priority.
  NVIC_EnableIRQ(TIM2_IRQn);
  NVIC_SetPriority(TIM2_IRQn, 0);


/*!
 * \brief Enables the "Cycle Timer", which will now fire interrupts that trigger
 * execution of the "App Loop" (--> \c TIM2_IRQHandler()).
 */
void start_app(void) 
  //Clear TIM2_IRQn update interrupt,
  TIM2->SR &= ~TIM_SR_UIF;

  //Enable the hardware interrupt.
  TIM2->DIER |= TIM_DIER_UIE;

  //Enable the timer.
  TIM2->CR1 |= TIM_CR1_CEN;


/*!
 * \brief Initializes any peripheral being used.
 */
void init(void) 
  //Disable interrupts.
  __disable_irq();

  config_output();
  config_blink_timer();

  //Enable interrupts.
  __enable_irq();


/*!
 * \brief Initializes the system and runs the application.
 */
int main(void) 
  init();

  start_app();

  while(1)
    __WFI();

  return EXIT_SUCCESS;


/*!
 * \brief This IRQ handler will be triggered every 10 us by the "Blink Timer".
 * This "time base" is used to blink a LED with a defined pattern (50 kHz,
 * 50% DS).
 */
void TIM2_IRQHandler(void) 
  //Clear TIM2 update interrupt flag.
  TIM2->SR &= ~TIM_SR_UIF;

  //Toggle PA11 (pin 5).
  GPIOA->ODR ^= (0x1u << 11);