stm32 adxl345 IIC 代码

以下是基于STM32的ADXL345 IIC通信代码：

#include "stm32f10x.h"

#define ADXL345_ADDR    0x53

void I2C_Configuration(void);
void ADXL345_Init(void);
void ADXL345_ReadData(uint8_t* pBuffer, uint16_t ReadAddr, uint16_t NumByteToRead);

int main(void)
{
    uint8_t buffer[6] = {0};
    I2C_Configuration();
    ADXL345_Init();
    ADXL345_ReadData(buffer, 0x32, 6); // 读取加速度计的X/Y/Z轴数据
    while (1);
}

void I2C_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    I2C_InitTypeDef I2C_InitStructure;

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

    // I2C1_SCL
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // I2C1_SDA
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStructure.I2C_OwnAddress1 = 0x00;
    I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStructure.I2C_ClockSpeed = 400000;

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

void ADXL345_Init(void)
{
    uint8_t buffer[2] = {0};
    buffer[0] = 0x31;
    buffer[1] = 0x0B;   // 设置数据范围为+-16g
    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C1, ADXL345_ADDR << 1, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C1, buffer[0]);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1, buffer[1]);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTOP(I2C1, ENABLE);
}

void ADXL345_ReadData(uint8_t* pBuffer, uint16_t ReadAddr, uint16_t NumByteToRead)
{
    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C1, ADXL345_ADDR << 1, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C1, ReadAddr);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C1, ADXL345_ADDR << 1, I2C_Direction_Receiver);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
    while (NumByteToRead)
    {
        if (NumByteToRead == 1)
        {
            I2C_AcknowledgeConfig(I2C1, DISABLE);
            I2C_GenerateSTOP(I2C1, ENABLE);
        }
        if (I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED))
        {
            *pBuffer = I2C_ReceiveData(I2C1);
            pBuffer++;
            NumByteToRead--;
        }
    }
    I2C_AcknowledgeConfig(I2C1, ENABLE);
}

该代码主要实现了ADXL345加速度计的初始化、读取X/Y/Z轴加速度数据。需要注意的是，这里的I2C使用了STM32内部的硬件I2C，因此需要进行相关的配置。同时，由于ADXL345采用的是7位地址，因此在发送地址时需要左移一位。