STM32F103 定时器的三种用法：PWM 输出、输入捕获与编码器接口

#include "stm32f1xx_hal.h"

TIM_HandleTypeDef htim1;                // TIM1 是高级定时器，CH1/CH2 = PA8/PA9
TIM_OC_InitTypeDef sConfigOC = {0};

void MotorPWM_Init(void)
{
    htim1.Instance = TIM1;
    htim1.Init.Prescaler = 71;          // 72MHz / 72 = 1MHz 计数
    htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim1.Init.Period = 999;            // 1MHz / 1000 = 1kHz
    htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
    HAL_TIM_PWM_Init(&htim1);

    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = 0;
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1);
    HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_2);

    HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);   // 内部会顺带打开 MOE
    HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_2);
}

/* 0~100 的百分比，转成 0~1000 的比较值 */
void Motor_SetSpeed(uint8_t percent)
{
    if (percent > 100) percent = 100;
    __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, percent * 10);
}

void Motor_Stop(void)
{
    __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, 0);
    __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_2, 0);
}

static volatile uint16_t lastEdge = 0;
static volatile uint8_t  phase = 0;     // 0: 等引导码下降沿，1: 已见到引导码
static volatile uint8_t  bitCount = 0;

void IR_Init(void)
{
    htim2.Instance = TIM2;
    htim2.Init.Prescaler = 71;          // 同样 1MHz，1 个计数 = 1us
    htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim2.Init.Period = 0xFFFF;
    HAL_TIM_IC_Init(&htim2);

    TIM_IC_InitTypeDef sIC = {0};
    sIC.ICPolarity  = TIM_INPUTCHANNELPOLARITY_FALLING;
    sIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
    sIC.ICPrescaler = TIM_ICPSC_DIV1;
    sIC.ICFilter    = 10;               // 滤掉接收头上的毛刺
    HAL_TIM_IC_ConfigChannel(&htim2, &sIC, TIM_CHANNEL_1);
    HAL_TIM_IC_Start_IT(&htim2, TIM_CHANNEL_1);
}

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
    if (htim->Instance != TIM2) return;

    uint16_t now   = (uint16_t)__HAL_TIM_GET_CAPTURE1(htim);
    uint16_t width = (uint16_t)(now - lastEdge);   // 无符号减法自动处理回绕
    lastEdge = now;

    if (phase == 0) {                   // 9ms 低电平引导码
        phase = 1;
    } else {
        NecBit_OnPulse(width);          // 560us 为 0，1690us 为 1
        if (++bitCount >= 32) {
            bitCount = 0;
            phase = 0;
        }
    }

    /* F103 的通用定时器没有 CCxNP 位，硬件双边沿只在 TIM1 上有，
       所以这里在中断里手动切换下一次要捕获的边沿 */
    __HAL_TIM_SET_CAPTUREPOLARITY(htim, TIM_CHANNEL_1,
        (phase & 1) ? TIM_INPUTCHANNELPOLARITY_RISING
                    : TIM_INPUTCHANNELPOLARITY_FALLING);
}

void Encoder_Init(void)
{
    TIM_Encoder_InitTypeDef sEnc = {0};

    htim4.Instance = TIM4;
    htim4.Init.Prescaler = 0;              // 编码器不要分频
    htim4.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim4.Init.Period = 0xFFFF;
    htim4.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim4.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;

    sEnc.EncoderMode  = TIM_ENCODERMODE_TI12;   // 4 倍频
    sEnc.IC1Polarity  = TIM_ICPOLARITY_RISING;
    sEnc.IC1Selection = TIM_ICSELECTION_DIRECTTI;
    sEnc.IC1Prescaler = TIM_ICPSC_DIV1;
    sEnc.IC1Filter    = 10;
    sEnc.IC2Polarity  = TIM_ICPOLARITY_RISING;
    sEnc.IC2Selection = TIM_ICSELECTION_DIRECTTI;
    sEnc.IC2Prescaler = TIM_ICPSC_DIV1;
    sEnc.IC2Filter    = 10;

    HAL_TIM_Encoder_Init(&htim4, &sEnc);
    HAL_TIM_Encoder_Start(&htim4, TIM_CHANNEL_ALL);
}

/* 每 10ms 调一次，返回这 10ms 内的增量 */
int16_t Encoder_ReadDelta(void)
{
    int16_t delta = (int16_t)__HAL_TIM_GET_COUNTER(&htim4);  // 16 位读是单条指令
    __HAL_TIM_SET_COUNTER(&htim4, 0);
    return delta;
}