用STM32中断方式实现两定位一脉冲旋转编码器

两定位一脉冲旋转编码器通常可以用来检测旋转轴的位置和旋转方向。在STM32中，我们可以通过使用定时器和外部中断来实现对旋转编码器的检测。

具体来说，我们可以将编码器的两个输出信号（A相和B相）连接到STM32的两个外部中断引脚（例如EXTI0和EXTI1），同时使用一个定时器来生成一个脉冲信号（例如TIM2的通道1）。当编码器旋转时，A相和B相信号会交替触发对应的外部中断，我们可以在中断处理函数中读取A相和B相的状态，从而确定旋转方向。同时，我们还可以在定时器溢出中断中生成一个脉冲信号，用来计算旋转的角度。

以下是一个简单的示例代码：

#include "stm32f4xx.h"

#define ENCODER_PORT        GPIOA
#define ENCODER_PIN_A       GPIO_Pin_0
#define ENCODER_PIN_B       GPIO_Pin_1
#define ENCODER_EXTI_LINE_A EXTI_Line0
#define ENCODER_EXTI_LINE_B EXTI_Line1
#define ENCODER_IRQ_A       EXTI0_IRQn
#define ENCODER_IRQ_B       EXTI1_IRQn

#define PULSE_TIMER         TIM2
#define PULSE_TIMER_CHANNEL TIM_Channel_1
#define PULSE_TIMER_IRQ     TIM2_IRQn

volatile int32_t encoder_count = 0;

void EXTI0_IRQHandler(void)
{
    if (EXTI_GetITStatus(ENCODER_EXTI_LINE_A) != RESET)
    {
        int32_t dir = GPIO_ReadInputDataBit(ENCODER_PORT, ENCODER_PIN_B) ? -1 : 1;
        encoder_count += dir;
        EXTI_ClearITPendingBit(ENCODER_EXTI_LINE_A);
    }
}

void EXTI1_IRQHandler(void)
{
    if (EXTI_GetITStatus(ENCODER_EXTI_LINE_B) != RESET)
    {
        int32_t dir = GPIO_ReadInputDataBit(ENCODER_PORT, ENCODER_PIN_A) ? 1 : -1;
        encoder_count += dir;
        EXTI_ClearITPendingBit(ENCODER_EXTI_LINE_B);
    }
}

void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(PULSE_TIMER, TIM_IT_Update) != RESET)
    {
        // do something with pulse timer
        TIM_ClearITPendingBit(PULSE_TIMER, TIM_IT_Update);
    }
}

void encoder_init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;

    // enable GPIO clock
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    // configure encoder pins as inputs
    GPIO_InitStructure.GPIO_Pin = ENCODER_PIN_A | ENCODER_PIN_B;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(ENCODER_PORT, &GPIO_InitStructure);

    // enable EXTI interrupts for encoder pins
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
    EXTI_InitStructure.EXTI_Line = ENCODER_EXTI_LINE_A | ENCODER_EXTI_LINE_B;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    // enable NVIC interrupts for encoder pins
    NVIC_InitStructure.NVIC_IRQChannel = ENCODER_IRQ_A;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
    NVIC_InitStructure.NVIC_IRQChannel = ENCODER_IRQ_B;
    NVIC_Init(&NVIC_InitStructure);

    // enable TIM2 clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    // configure TIM2 as pulse timer
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(PULSE_TIMER, &TIM_TimeBaseStructure);
    TIM_OCStructInit(&TIM_OCInitStructure);
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0xFFFF;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(PULSE_TIMER, &TIM_OCInitStructure);
    TIM_ITConfig(PULSE_TIMER, TIM_IT_Update, ENABLE);
    TIM_Cmd(PULSE_TIMER, ENABLE);

    // enable NVIC interrupts for TIM2
    NVIC_InitStructure.NVIC_IRQChannel = PULSE_TIMER_IRQ;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

在这个示例代码中，我们使用了GPIOA的0号和1号引脚作为编码器的A相和B相信号，同时使用了TIM2作为脉冲信号的定时器。在编码器的两个外部中断处理函数中，我们读取了对应的IO口状态，并根据旋转方向更新了计数器。在定时器中断处理函数中，我们可以生成一个脉冲信号，并在需要时进行处理。

需要注意的是，本示例代码中没有进行初始化操作，因此需要根据具体情况进行初始化。同时，计数器的值可能会溢出，需要进行处理。