stm32的IIc总线--超声波测距代码

以下是基于STM32的I2C总线和超声波传感器的测距代码示例：

#include "stm32f10x.h"
#include "stdio.h"

#define I2C_Speed              400000
#define I2C1_SLAVE_ADDRESS7    0xE0
#define I2C_PageSize           8

#define HCSR04_ADDRESS         0xE0
#define HCSR04_RANGE_CMD       0x51

void GPIO_Configuration(void);
void I2C_Configuration(void);
void HCSR04_Init(void);
void HCSR04_ReadDistance(uint16_t *distance);

int main(void)
{
    uint16_t distance;
	
    GPIO_Configuration();
    I2C_Configuration();
    HCSR04_Init();
	
    while (1)
    {
        HCSR04_ReadDistance(&distance);
        printf("Distance: %d cm\r\n", distance);
        delay_ms(1000);
    }
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void I2C_Configuration(void)
{
    I2C_InitTypeDef I2C_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    I2C_DeInit(I2C1);

    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStructure.I2C_OwnAddress1 = I2C1_SLAVE_ADDRESS7;
    I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStructure.I2C_ClockSpeed = I2C_Speed;

    I2C_Cmd(I2C1, ENABLE);
    I2C_Init(I2C1, &I2C_InitStructure);
}

void HCSR04_Init(void)
{
    uint8_t cmd[1];

    cmd[0] = HCSR04_RANGE_CMD;

    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

    I2C_Send7bitAddress(I2C1, HCSR04_ADDRESS, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

    I2C_SendData(I2C1, cmd[0]);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    I2C_GenerateSTOP(I2C1, ENABLE);
}

void HCSR04_ReadDistance(uint16_t *distance)
{
    uint8_t data[2];

    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

    I2C_Send7bitAddress(I2C1, HCSR04_ADDRESS, I2C_Direction_Receiver);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    data[0] = I2C_ReceiveData(I2C1);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    data[1] = I2C_ReceiveData(I2C1);

    I2C_GenerateSTOP(I2C1, ENABLE);

    *distance = ((uint16_t)data[0] << 8) | data[1];
}

在代码中，我们首先进行GPIO和I2C总线的初始化，然后使用`HCSR04_Init()`函数发送命令给超声波传感器，开始一次测距。最后，使用`HCSR04_ReadDistance()`函数读取超声波传感器返回的距离数据，并将其打印到串口上。

注意：此代码仅供参考，实际使用时需要根据具体的硬件和软件环境进行修改和优化。