写一段stm32hal库pwm控制舵机的代码

以下是一段使用STM32 HAL库实现PWM控制舵机的代码：

#include "stm32f4xx_hal.h"

#define SERVO_PWM_TIM TIM3
#define SERVO_PWM_CHANNEL TIM_CHANNEL_2

void servo_pwm_init(void)
{
    TIM_HandleTypeDef htim;

    /* Enable TIM3 clock */
    __HAL_RCC_TIM3_CLK_ENABLE();

    /* Configure TIM3 as PWM */
    htim.Instance = SERVO_PWM_TIM;
    htim.Init.Prescaler = 0;
    htim.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim.Init.Period = 20000; // 20ms period for 50Hz PWM
    htim.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    HAL_TIM_PWM_Init(&htim);

    /* Configure PWM output */
    TIM_OC_InitTypeDef sConfigOC;
    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = 1500; // 1.5ms duty cycle for middle position
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    HAL_TIM_PWM_ConfigChannel(&htim, &sConfigOC, SERVO_PWM_CHANNEL);

    /* Start PWM */
    HAL_TIM_PWM_Start(&htim, SERVO_PWM_CHANNEL);
}

void servo_set_position(float angle)
{
    /* Calculate pulse width */
    float pulse_width = angle / 180.0f * 1000.0f + 1000.0f;

    /* Set PWM pulse width */
    TIM_OC_InitTypeDef sConfigOC;
    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = pulse_width;
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    HAL_TIM_PWM_ConfigChannel(&htim, &sConfigOC, SERVO_PWM_CHANNEL);
}

以上代码中，`servo_pwm_init()`函数用于初始化PWM输出，并启动定时器。`servo_set_position()`函数用于设置舵机角度，计算出对应的PWM脉宽并设置到定时器输出通道上。其中，定时器使用了TIM3，输出通道为2，PWM周期为20ms，对应50Hz的PWM信号。舵机角度范围为0-180度，对应的PWM脉宽范围为1-2ms。中间位置为90度，对应1.5ms的PWM脉宽。