启用外部中断ARM Cortex-M0 +STM32G070

问题描述

我试图对STM32微控制器的编程有一个基本的了解。我试图通过设置所有适当的寄存器（无外部库/定义），通过按钮使用外部中断来切换LED的状态。我似乎无法使中断例程正常工作，控制从未传递给处理程序。

这是我用来将PC-13（根据Nucleo-G070RB板连接有一个按钮）设置为外部中断的原因：

RCC_APBENR2  |= 0b1 <<  0; // Enable SYSCFGEN
RCC_IOPENR   |= 0b1 <<  2; // Enable PORTC
EXTI_RTSR1   |= 0b1 << 13; // Enable interrupt on rising edge at EXTI line 13
EXTI_EXTICR4 |= 0x2 <<  8; // Set PC-13 as GPIO pin for interrupt
EXTI_IMR1    |= 0x1 << 13; // Unmask EXTI line 13

NVIC_ISER    |= 0b1 <<  7; // Enable interrupts for EXTI4_15

我不确定我缺少什么。

这是完整的代码：

#include <stdint.h>
#include <stdio.h>

#define RCC_IOPENR   *((uint32_t volatile *) 0x40021034)
#define RCC_APBENR2  *((uint32_t volatile *) 0x40021040)

#define GPIOA_MODER  *((uint32_t volatile *) 0x50000000)
#define GPIOA_IDR    *((uint32_t volatile *) 0x50000010)
#define GPIOA_ODR    *((uint32_t volatile *) 0x50000014)

#define GPIOC_MODER  *((uint32_t volatile *) 0x50000800)
#define GPIOC_IDR    *((uint32_t volatile *) 0x50000810)
#define GPIOC_ODR    *((uint32_t volatile *) 0x50000814)

#define NVIC_ISER    *((uint32_t volatile *) 0xE000E100)

#define EXTI_RTSR1   *((uint32_t volatile *) 0x40021800)
#define EXTI_EXTICR1 *((uint32_t volatile *) (0x40021800 + 0x060 + 0x4 * 0))
#define EXTI_EXTICR2 *((uint32_t volatile *) (0x40021800 + 0x060 + 0x4 * 1))
#define EXTI_EXTICR3 *((uint32_t volatile *) (0x40021800 + 0x060 + 0x4 * 2))
#define EXTI_EXTICR4 *((uint32_t volatile *) (0x40021800 + 0x060 + 0x4 * 3))
#define EXTI_IMR1    *((uint32_t volatile *) (0x40021800 + 0x080))
#define EXTI_RPR1    *((uint32_t volatile *) (0x40021800 + 0x00C))

void button_init();
extern void initialise_monitor_handles();

uint8_t volatile g_button_pressed = 0;

int main(void) {
    //asm volatile ("cpsie i");
    initialise_monitor_handles();

    //printf("Hello World!\n");

    RCC_IOPENR  |= 0b1 << 0;         // Enable PORTA
    GPIOA_MODER &= ~(0b11 << (2*5)); // Clear MODE bits for 5th pin (PA-5)
    GPIOA_MODER |= 0b1 << (2*5);     // Set MODE bits for 5th pin (PA-5) to 01 (set output)
    GPIOC_MODER &= ~(0b11 << (2*13)); // Clear MODE bits for 13th pin (PC-13) (set input)

    button_init();

    while(1) {
        if (g_button_pressed) {
            GPIOA_ODR ^= 0b1 << 5;
            printf("Button pressed\n");
            g_button_pressed = 0;
        }
    }
}

void button_init() {
    RCC_APBENR2  |= 0b1 <<  0; // Enable SYSCFGEN
    RCC_IOPENR   |= 0b1 <<  2; // Enable PORTC
    EXTI_RTSR1   |= 0b1 << 13; // Enable interrupt on rising edge at EXTI line 13
    EXTI_EXTICR4 |= 0x2 <<  8; // Set PC-13 as GPIO pin for interrupt
    EXTI_IMR1    |= 0x1 << 13; // Unmask EXTI line 13

    NVIC_ISER    |= 0b1 <<  7; // Enable interrupts for EXTI4_15
}

void EXTI4_15_IRQHandler(void) {
    g_button_pressed = 1;
    printf("Button pressed\n");
    EXTI_RPR1 |= 0xFFFF << 0;
}

我将STM32CubeIDE与默认编译器一起使用，并通过OpenOCD半主机进行打印。

所以，我的问题是，我错过了一步还是做错了什么？

解决方法

所以，我弄清楚了我的愚蠢错误。我非常专注于尝试了解设置外部中断时出了什么问题，我并没有真正检查是否正确设置了按钮。

我试图将PC13设置为输入：

GPIOC_MODER &= ~(0b11 << (2*13)); // Clear MODE bits for 13th pin (PC-13) (set input)

在调用button_init()函数之前，该函数通过以下方式启用GPIOC的时钟：

RCC_IOPENR   |= 0b1 <<  2; // Enable PORTC

由于未启用GPIOC，所以也未将PC13设置为输入，因此没有可检测的内容。

这是固定的代码：（我也将其更新为使用CMSIS stm32标头，如P__J__所建议）

#define STM32G070xx
#include "stm32g0xx.h"

uint8_t volatile g_button_pressed = 0;

void button_init();
//extern void initialise_monitor_handles();

int main(void) {
//  initialise_monitor_handles();

    //printf("Hello World!\n");
    RCC->IOPENR  |= 0b1 << 0;         // Enable PORTA
    GPIOA->MODER &= ~(0b11 << (2*5)); // Clear MODE bits for 5th pin (PA-5)
    GPIOA->MODER |= 0b1 << (2*5);     // Set MODE bits for 5th pin (PA-5) to 01 (set output)

    button_init();

    while(1) {
        if (g_button_pressed) {
            GPIOA->ODR ^= 0b1 << 5;
//          printf("Button pressed! Yay!\n");
            g_button_pressed = 0;
        }
    }
}

void button_init() {
    // RCC->APBENR2    |= (uint32_t) (0b1 <<  0); // Enable SYSCFGEN
    RCC->IOPENR     |= (uint32_t) (0b1 <<  2); // Enable PORTC
    GPIOC->MODER    &= ~(0b11 << (2*13));      // Clear MODE bits for 13th pin (PC-13) (set input)

    EXTI->RTSR1     |= (uint32_t) (0b1 << 13); // Enable interrupt on rising edge at EXTI line 13
    EXTI->EXTICR[3] |= (uint32_t) (0x2 <<  8); // Set PC-13 as GPIO pin for interrupt
    EXTI->IMR1      |= (uint32_t) (0x1 << 13); // Unmask EXTI line 13

    NVIC->ISER[0]   |= (uint32_t) (0b1 <<  7); // Enable interrupts for EXTI4_15
}

void EXTI4_15_IRQHandler(void) {
    g_button_pressed = 1;
//  printf("Button pressed\n");
    EXTI->RPR1 = 0b1 << 13;
}