超声波无法测距/* USER CODE BEGIN Header */ /** ****************************************************************************** * @file : main.c * @brief : Main program body ****************************************************************************** * @attention * * Copyright (c) 2025 STMicroelectronics. * All rights reserved. * * This software is licensed under terms that can be found in the LICENSE file * in the root directory of this software component. * If no LICENSE file comes with this software, it is provided AS-IS. * ****************************************************************************** */ /* USER CODE END Header */ /* Includes ------------------------------------------------------------------*/ #include "main.h" #include "adc.h" #include "tim.h" #include "gpio.h" /* Private includes ----------------------------------------------------------*/ /* USER CODE BEGIN Includes */ /* USER CODE END Includes */ /* Private typedef -----------------------------------------------------------*/ /* USER CODE BEGIN PTD */ /* USER CODE END PTD */ /* Private define ------------------------------------------------------------*/ /* USER CODE BEGIN PD */ /* USER CODE END PD */ /* Private macro -------------------------------------------------------------*/ /* USER CODE BEGIN PM */ /* USER CODE END PM */ /* Private variables ---------------------------------------------------------*/ /* USER CODE BEGIN PV */ int Turn_Pwm = 0; uint8_t stop_flag = 0; // 停止标志位 uint8_t void_flag = 0; // 停止标志位 float feature_time = 0; // 特征区域经过时间 // 存放测距距离 /* USER CODE END PV */ /* Private function prototypes -----------------------------------------------*/ void SystemClock_Config(void); void TIM4_Dealy_us(uint16_t n_us); double get_distance(); /* USER CODE BEGIN PFP */ /* USER CODE END PFP */ /* Private user code ---------------------------------------------------------*/ /* USER CODE BEGIN 0 */ /* USER CODE END 0 */ /** * @brief The application entry point. * @retval int */ int main(void) { /* USER CODE BEGIN 1 */ /* USER CODE END 1 */ /* MCU Configuration--------------------------------------------------------*/ /* Reset of all peripherals, Initializes the Flash interface and the Systick. */ HAL_Init(); /* USER CODE BEGIN Init */ /* USER CODE END Init */ /* Configure the system clock */ SystemClock_Config(); /* USER CODE BEGIN SysInit */ /* USER CODE END SysInit */ /* Initialize all configured peripherals */ MX_GPIO_Init(); MX_ADC1_Init(); MX_TIM3_Init(); MX_TIM4_Init(); /* USER CODE BEGIN 2 */ HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_4); HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_2); // HAL_Delay(3000); /* USER CODE END 2 */ /* Infinite loop */ /* USER CODE BEGIN WHILE */ while (1) {float dis = 0; dis = get_distance(); HAL_GPIO_WritePin(LED_GPIO_Port,LED_Pin,GPIO_PIN_SET); //if(dis < 20.0) // 距离小于20cm亮灯 // HAL_GPIO_WritePin(LED_GPIO_Port,LED_Pin,GPIO_PIN_RESET); //else //HAL_GPIO_WritePin(LED_GPIO_Port,LED_Pin,GPIO_PIN_SET); //HAL_Delay(100); // 0.1s测量一次} /* int pwmVal_R = 200; int pwmVal_L = 200; RD_TSL(); Find_CCD_Zhongzhi(); // 计算特征区域经过时间(假设采样频率为100Hz) feature_time = ccd_data_process(ADV, 50.0f); // 检查是否达到积分阈值 if (feature_time >= INTEGRATION_THRESHOLD) { stop_flag = 1; } if (!stop_flag) { Turn_Pwm = turn(CCD_Zhongzhi, 0); // 右侧电机控制 if (pwmVal_R - Turn_Pwm > 0) { HAL_GPIO_WritePin(GPIOA, R1_Pin, 1); HAL_GPIO_WritePin(GPIOA, R2_Pin, 0); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, pwmVal_R - Turn_Pwm); } else if (pwmVal_R - Turn_Pwm < 0) { HAL_GPIO_WritePin(GPIOA, R1_Pin, 0); HAL_GPIO_WritePin(GPIOA, R2_Pin, 1); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, -pwmVal_R + Turn_Pwm); } else { HAL_GPIO_WritePin(GPIOA, R1_Pin, 0); HAL_GPIO_WritePin(GPIOA, R2_Pin, 0); } // 左侧电机控制 if (pwmVal_L + Turn_Pwm > 0) { HAL_GPIO_WritePin(GPIOA, L1_Pin, 1); HAL_GPIO_WritePin(GPIOA, L2_Pin, 0); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, pwmVal_L + Turn_Pwm); } else if (pwmVal_L + Turn_Pwm < 0) { HAL_GPIO_WritePin(GPIOA, L1_Pin, 0); HAL_GPIO_WritePin(GPIOA, L2_Pin, 1); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, -pwmVal_L - Turn_Pwm); } else { HAL_GPIO_WritePin(GPIOA, L1_Pin, 0); HAL_GPIO_WritePin(GPIOA, L2_Pin, 0); } } else if(void_flag==1){ HAL_GPIO_WritePin(GPIOA, R1_Pin, 1); HAL_GPIO_WritePin(GPIOA, R2_Pin, 0); HAL_GPIO_WritePin(GPIOA, L1_Pin, 1); HAL_GPIO_WritePin(GPIOA, L2_Pin, 0); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, 350); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2,100);//右边 HAL_Delay(300); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, 350);//右边 __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4,100); HAL_Delay(300); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, 220);//右边 __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4,200); HAL_Delay(100); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, 350);//右边 __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4,100); HAL_Delay(300); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, 350); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2,100);//右边 HAL_Delay(300); stop_flag = 0; // __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, -pwmVal_R); // __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, pwmVal_L); } else { // 停止小车 HAL_GPIO_WritePin(GPIOA, R1_Pin, 1); HAL_GPIO_WritePin(GPIOA, R2_Pin, 1); HAL_GPIO_WritePin(GPIOA, L1_Pin, 1); HAL_GPIO_WritePin(GPIOA, L2_Pin, 1); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_4, 0); __HAL_TIM_SetCompare(&htim3, TIM_CHANNEL_2, 0); HAL_GPIO_WritePin(LED_GPIO_Port,LED_Pin,GPIO_PIN_RESET); } Dly_us(); */ /* USER CODE END WHILE */ /* USER CODE BEGIN 3 */ } /* USER CODE END 3 */ } /** * @brief System Clock Configuration * @retval None */ void TIM4_Dealy_us(uint16_t n_us) { __HAL_TIM_ENABLE(&htim4); __HAL_TIM_SetCounter(&htim4,0); uint32_t timeout = 0; while(__HAL_TIM_GetCounter(&htim4) < ((1 * n_us)-1)) { if(timeout++ > n_us * 2) break; // 超时保护,避免死循环 } __HAL_TIM_DISABLE(&htim4); } double get_distance() { int cnt = 0; // 存放定时器计次次数 // 1.给Trig端口20us(至少10us)高电平 HAL_GPIO_WritePin(Trig_GPIO_Port,Trig_Pin,GPIO_PIN_SET); TIM4_Dealy_us(20); HAL_GPIO_WritePin(Trig_GPIO_Port,Trig_Pin,GPIO_PIN_RESET); // 2.波发出去时启动定时器 while(HAL_GPIO_ReadPin(Echo_GPIO_Port,Echo_Pin)==GPIO_PIN_RESET); HAL_TIM_Base_Start(&htim4); __HAL_TIM_SetCounter(&htim4,0); // 将Timer4的值重置为指定值0 // 3.由高电平到低电平表示波已返回,关闭定时器 while(HAL_GPIO_ReadPin(Echo_GPIO_Port,Echo_Pin)==GPIO_PIN_SET); HAL_TIM_Base_Stop(&htim4); cnt = __HAL_TIM_GetCounter(&htim4); // 获取Timer4当前计数值 // 4.计算时间和距离 // cnt为计数次数,1次1us,cnt次即cntus,×0.000001转换为s,×340÷2得到距离,单位为m,×100转换为cm return (cnt*340/2*0.000001*100); // 单位为cm } void SystemClock_Config(void) { RCC_OscInitTypeDef RCC_OscInitStruct = {0}; RCC_ClkInitTypeDef RCC_ClkInitStruct = {0}; RCC_PeriphCLKInitTypeDef PeriphClkInit = {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_MUL2; 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_DIV1; RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1; if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK) { Error_Handler(); } PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC; PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV2; if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) { Error_Handler(); } } /* USER CODE BEGIN 4 */ /* USER CODE END 4 */ /** * @brief This function is executed in case of error occurrence. * @retval None */ void Error_Handler(void) { /* USER CODE BEGIN Error_Handler_Debug */ /* User can add his own implementation to report the HAL error return state */ __disable_irq(); while (1) { } /* USER CODE END Error_Handler_Debug */ } #ifdef USE_FULL_ASSERT /** * @brief Reports the name of the source file and the source line number * where the assert_param error has occurred. * @param file: pointer to the source file name * @param line: assert_param error line source number * @retval None */ void assert_failed(uint8_t *file, uint32_t line) { /* USER CODE BEGIN 6 */ /* User can add his own implementation to report the file name and line number, ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */ /* USER CODE END 6 */ } #endif /* USE_FULL_ASSERT */
时间: 2025-05-28 19:45:15 浏览: 37
### 超声波测距功能实现分析
在使用STM32 HAL库实现超声波测距的过程中,`get_distance` 函数可能无法正确返回距离值的原因通常涉及硬件配置、软件逻辑以及计算公式的准确性。以下是可能导致该问题的具体原因及其解决方案:
#### 1. **触发信号未正确生成**
如果触发信号未能达到至少10μs的高电平,则模块不会启动测距操作。需确认`Trigger_HC_SR04()`函数中的延时是否满足要求。
```c
void Trigger_HC_SR04(void) {
HAL_GPIO_WritePin(TRIGGER_PORT, TRIGGER_PIN, GPIO_PIN_SET);
__HAL_TIM_SET_COUNTER(&htim2, 0); // 清零计数器
while (__HAL_TIM_GET_COUNTER(&htim2) < 15); // 约等于10μs
HAL_GPIO_WritePin(TRIGGER_PORT, TRIGGER_PIN, GPIO_PIN_RESET);
}
```
上述代码片段展示了如何利用定时器精确控制触发信号宽度[^1]。
---
#### 2. **回响时间测量错误**
测量Echo引脚高电平持续时间的功能由`Measure_Echo_Time()`实现。如果此部分存在问题,可能会导致后续的距离计算偏差。
```c
uint32_t Measure_Echo_Time(void) {
uint32_t startTime, endTime;
while(HAL_GPIO_ReadPin(ECHO_PORT, ECHO_PIN) == GPIO_PIN_RESET); // 等待上升沿
startTime = __HAL_TIM_GET_COUNTER(&htim2);
while(HAL_GPIO_ReadPin(ECHO_PORT, ECHO_PIN) == GPIO_PIN_SET); // 等待下降沿
endTime = __HAL_TIM_GET_COUNTER(&htim2);
return (endTime - startTime); // 返回脉冲宽度(单位:TIM时钟周期)
}
```
此处需要注意的是,定时器的频率设置应与实际需求匹配,以确保精度[^1]。
---
#### 3. **距离计算公式错误**
使用以下公式将回响时间转换为距离:
\[
\text{Distance} = (\text{Time} * \text{Speed of Sound}) / 2
\]
在程序中可以表示为:
```c
float Calculate_Distance(uint32_t time) {
const float sound_speed = 340.0f; // 声速(m/s)
const float timer_frequency = 8e6; // 定时器频率(假设为8MHz)
float duration_seconds = ((float)time / timer_frequency); // 将计数值转化为秒
return (duration_seconds * sound_speed) / 2.0f; // 单位:米
}
```
若定时器频率设定不当或声速取值有误,均会影响最终结果[^2]。
---
#### 4. **硬件连接异常**
检查HC-SR04模块与STM32之间的连线是否存在松动或其他物理损坏情况。特别注意Trig和Echo引脚对应的GPIO端口初始化是否正确[^1]。
---
#### 5. **浮点运算空间不足**
当目标设备资源有限时,复杂的浮点运算可能导致溢出等问题。建议参考自定义浮点转字符串方法来减少内存占用[^3]。
---
### 综合调试建议
为了快速定位问题所在,可依次执行以下验证步骤:
- 打印中间变量(如`echo_time`),观察其变化趋势;
- 替换现有算法组件逐一排查潜在缺陷;
- 利用示波器监测关键节点电压波动特征。
```python
// 示例:通过UART打印调试信息
void Debug_Print(float value) {
char buffer[16];
FloatToString(value, buffer); // 自定义函数
HAL_UART_Transmit(&huart1, (uint8_t*)buffer, strlen(buffer), HAL_MAX_DELAY);
}
```
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