文章目录

一、舵机驱动原理    

二、代码实现

三、总结&注意事项

舵机驱动原理

SG90舵机的内部存在一个差速齿轮组，其控制依赖于一个周期为20ms（频率为50Hz）的PWM信号。舵机的转动角度由高电平的脉冲宽度决定：

通过调节PWM的占空比，可以达到控制舵机转动角度的目的；关于PWM的介绍详见

STM32系列教程（十）：基于定时器的输出比较模式输出PWM

代码实现

系统时钟设置为72MHz，APB2总线时钟也为72MHz，TIM1的预分频系数设置为71，将72MHz分频到1MHz；周期设置为19999，产生20ms周期；PWM极性为高电平有效

调用 SG90_SetAngle函数设置目标角度

main.c

#include "main.h"
#include "tim.h"
#include "gpio.h"

void SystemClock_Config(void);

void SG90_SetAngle(TIM_HandleTypeDef *htim, uint32_t Channel, float angle);

/**
  * @brief  设置SG90舵机角度
  * @param  htim: 定时器句柄
  * @param  Channel: 定时器通道
  * @param  angle: 目标角度 (0-180)
  * @retval None
  */
void SG90_SetAngle(TIM_HandleTypeDef *htim, uint32_t Channel, float angle)
{
  uint16_t pulse_value;
  pulse_value = (angle / 180.0) * 2000 + 500;
  __HAL_TIM_SET_COMPARE(htim, Channel, pulse_value);
}

int main(void)
{
  HAL_Init();

  SystemClock_Config();

  MX_GPIO_Init();
  MX_TIM1_Init();

  HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1); // 启动TIM1的通道1输出PWM

while (1)
  {
    // 示例：让舵机在0°, 90°, 180°之间往复运动
    SG90_SetAngle(&htim1, TIM_CHANNEL_1, 0);
    HAL_Delay(1000);

    SG90_SetAngle(&htim1, TIM_CHANNEL_1, 90);
    HAL_Delay(1000);

    SG90_SetAngle(&htim1, TIM_CHANNEL_1, 180);
    HAL_Delay(1000);

    SG90_SetAngle(&htim1, TIM_CHANNEL_1, 90);
    HAL_Delay(1000);
  }
}

static void MX_TIM1_Init(void)
{
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
  TIM_OC_InitTypeDef sConfigOC = {0};
  TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};

  htim1.Instance = TIM1;
  htim1.Init.Prescaler = 72-1;           // 预分频器，72MHz/72 = 1MHz
  htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim1.Init.Period = 20000-1;           // 自动重装载值，20ms周期
  htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim1.Init.RepetitionCounter = 0;
  htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }

  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }

if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
  {
    Error_Handler();
  }

  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }

  sConfigOC.OCMode = TIM_OCMODE_PWM1;
  sConfigOC.Pulse = 0;                   // 初始占空比为0
  sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
  sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
  sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
  sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
  sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }

  sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
  sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
  sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
  sBreakDeadTimeConfig.DeadTime = 0;
  sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
  sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
  sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
  {
    Error_Handler();
  }

  HAL_TIM_MspPostInit(&htim1);
}

static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /* Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_RESET);

  /* Configure TIM1 CH1 output pin (PA8) */
  GPIO_InitStruct.Pin = GPIO_PIN_8;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
}

void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

总结&注意事项

ADC的总转换时间由采样时间和固定转换周期（12.5个ADC时钟周期）组成：转换时间=采样时间+12.5个周期Tconv=采样时间+12.5个周期；采样时间可根据信号源阻抗和精度要求在1.5、7.5、13.5、28.5、41.5、55.5、71.5和239.5个周期中选择