基于stm32f401rct6开发HC-SR04的代码，要求使用hal库

基于STM32F401RCT6开发HC-SR04超声波测距模块的代码通常会利用HAL库（Hardware Abstraction Layer，硬件抽象层）来简化外围设备操作。以下是一个简化的示例代码，它演示了如何配置GPIO、TIM以及串口通信来读取HC-SR04的数据：

#include "stm32f4xx_hal.h"
#include "usart.h"

// HC-SR04初始化结构体
typedef struct {
    GPIO_TypeDef *echoPin;
    GPIO_TypeDef *triggerPin;
    UART_HandleTypeDef UsartHandle;
} UltrasonicSensor;

void ultrasonicInit(UltrasonicSensor* sensor, uint8_t echoPin, uint8_t triggerPin, USART_HandleTypeDef *usart) {
    // GPIO配置
    sensor->echoPin = GPIOA;
    sensor->triggerPin = GPIOB;

    GPIO_InitTypeDef gpioInitStruct;

    gpioInitStruct.Pin = GPIO_PIN_5 | GPIO_PIN_6; // 例如，如果echoPin和triggerPin分别是PA5和PB6
    gpioInitStruct.Mode = GPIO_MODE_AF_PP;
    gpioInitStruct.Pull = GPIO_NOPULL;
    gpioInitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
    gpioInitStruct.Alternate = GPIO_AF7_USART2; // 如果USART2用于通信

    HAL_GPIO_Init(sensor->echoPin, &gpioInitStruct);
    HAL_GPIO_Init(sensor->triggerPin, &gpioInitStruct);

    // TIM配置
    TIM_HandleTypeDef TimHandle;
    TimHandle.Instance = TIM2;
    TimHandle.Init.Prescaler = 8399; // 根据实际晶振频率计算合适的计数周期
    TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
    TimHandle.Init.Period = 20000 - TimHandle.Init.Prescaler; // 超声波传播时间+测量延迟
    TimHandle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    HAL_TIM_Base_Init(&TimHandle);

    // USART配置
    usart->Instance = sensor->UsartHandle.Instance;
    HAL_UART_Init(usart);
}

int32_t getDistance(UltrasonicSensor* sensor) {
    HAL_Delay(10); // 等待触发脉冲发射
    HAL_GPIO_WritePin(sensor->triggerPin, GPIO_PIN_SET); // 发射触发信号
    HAL_Delay(10); // 等待Echo脉冲检测

    HAL_GPIO_WritePin(sensor->triggerPin, GPIO_PIN_RESET); // 释放触发信号

    uint32_t pulseStart, pulseEnd;
    HAL_GPIO_ReadPin(sensor->echoPin, &pulseStart); // 开始读取回波信号
    while (HAL_GPIO_ReadPin(sensor->echoPin, NULL) == GPIO_PIN_RESET) {
        if (HAL_GetTick() > pulseStart) {
            pulseStart = HAL_GetTick();
        }
    }

    while (HAL_GPIO_ReadPin(sensor->echoPin, NULL) == GPIO_PIN_SET) {
        if (HAL_GetTick() > pulseStart) {
            pulseEnd = HAL_GetTick();
        }
    }

    int32_t distance = ((pulseEnd - pulseStart) * 0.034 / 2); // 使用公式计算距离，假设声音速度为343 m/s
    return distance;
}

int main(void) {
    UltrasonicSensor sensor = {0};
    // ... 初始化传感器并连接到HAL UART
    // ...

    while (1) {
        float distance_cm = getDistance(&sensor);
        printf("Distance: %0.2f cm\n", distance_cm);
        HAL_Delay(1000);
    }

    return 0;
}