使用stm32标准库函数写出iic超声波测距代码

以下是基于STM32标准库函数的IIC超声波测距代码实现：

#include "stm32f10x.h"

#define I2C_SPEED 100000 // I2C速度，单位：Hz
#define I2C_TIMEOUT 1000 // I2C超时时间，单位：ms

#define ADDR_WR 0xE0     // 超声波I2C写地址
#define ADDR_RD 0xE1     // 超声波I2C读地址

#define CMD_RANGE 0x51   // 测距命令

I2C_InitTypeDef I2C_InitStruct;

// I2C总线初始化
void I2C_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); // 使能GPIOB时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);  // 使能I2C1时钟
    // PB6-I2C1_SCL、PB7-I2C1_SDA
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStruct);
    I2C_StructInit(&I2C_InitStruct);
    I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStruct.I2C_OwnAddress1 = 0x00;
    I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStruct.I2C_ClockSpeed = I2C_SPEED;
    I2C_Init(I2C1, &I2C_InitStruct);
    I2C_Cmd(I2C1, ENABLE);
}

// 向超声波发送命令
void Ultrasonic_SendCmd(uint8_t cmd)
{
    uint32_t timeout = I2C_TIMEOUT;
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY))
    {
        if ((timeout--) == 0)
            return;
    }
    I2C_GenerateSTART(I2C1, ENABLE);
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT))
    {
        if ((timeout--) == 0)
            return;
    }
    I2C_Send7bitAddress(I2C1, ADDR_WR, I2C_Direction_Transmitter);
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
    {
        if ((timeout--) == 0)
            return;
    }
    I2C_SendData(I2C1, cmd);
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
    {
        if ((timeout--) == 0)
            return;
    }
    I2C_GenerateSTOP(I2C1, ENABLE);
}

// 读取超声波测距数据
uint16_t Ultrasonic_ReadData(void)
{
    uint16_t data = 0;
    uint8_t databuf[2];
    uint32_t timeout = I2C_TIMEOUT;
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY))
    {
        if ((timeout--) == 0)
            return data;
    }
    I2C_GenerateSTART(I2C1, ENABLE);
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT))
    {
        if ((timeout--) == 0)
            return data;
    }
    I2C_Send7bitAddress(I2C1, ADDR_RD, I2C_Direction_Receiver);
    timeout = I2C_TIMEOUT;
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
    {
        if ((timeout--) == 0)
            return data;
    }
    I2C_AcknowledgeConfig(I2C1, DISABLE);
    I2C_GenerateSTOP(I2C1, ENABLE);
    timeout = I2C_TIMEOUT;
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET)
    {
        if ((timeout--) == 0)
            return data;
    }
    databuf[0] = I2C_ReceiveData(I2C1);
    timeout = I2C_TIMEOUT;
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET)
    {
        if ((timeout--) == 0)
            return data;
    }
    databuf[1] = I2C_ReceiveData(I2C1);
    data = (databuf[0] << 8) + databuf[1];
    return data;
}

int main(void)
{
    uint16_t distance = 0;
    I2C_Configuration(); // I2C总线初始化
    while (1)
    {
        Ultrasonic_SendCmd(CMD_RANGE); // 发送测距命令
        distance = Ultrasonic_ReadData(); // 读取测距数据
        // 处理测距数据
        // ...
    }
}

其中，`I2C_Configuration()`函数用于初始化I2C总线，`Ultrasonic_SendCmd()`函数用于向超声波发送命令，`Ultrasonic_ReadData()`函数用于读取超声波测距数据。通过不断发送测距命令和读取测距数据，可实现超声波连续测距功能。