如何使用STM32F4从MPU6050读取数据

Question

我需要监控对象的加速度。我使用的是MPU6050(加速度计和陀螺仪(和控制器STM32F401RBT6。下面的代码是我为此使用的解决方案。

#define MPU6050_ADDR 0xD0
#define SMPLRT_DIV_REG 0x19
#define GYRO_CONFIG_REG 0x1B
#define ACCEL_CONFIG_REG 0x1C
#define ACCEL_XOUT_H_REG 0x3B
#define TEMP_OUT_H_REG 0x41
#define GYRO_XOUT_H_REG 0x43
#define PWR_MGMT_1_REG 0x6B
#define WHO_AM_I_REG 0X75
uint16_t Accel_X_RAW,Accel_Y_RAW,Accel_Z_RAW;
uint16_t Ax,Ay,Az;
char buffer[10];
void MPU6050_Init(void)
{
uint8_t check, data;
HAL_I2C_Mem_Read(&hi2c3,MPU6050_ADDR,WHO_AM_I_REG,1,&check,1,100);
if(check == 104)
{
data = 0x07;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,SMPLRT_DIV_REG,1,&data,1,50);
HAL_Delay(50);
data = 0x00;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,ACCEL_CONFIG_REG,1,&data,1,50);
HAL_Delay(50);
data = 0x00;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,GYRO_CONFIG_REG,1,&data,1,50);
HAL_Delay(50);
data = 0;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,PWR_MGMT_1_REG,1,&data,1,50);
HAL_Delay(50);
}
}
void MPU6050_Read_Accel(void)
{
uint8_t recData[6];
for(int i=0;i<6;i++) recData[i] = 0;
HAL_I2C_Mem_Read(&hi2c3,MPU6050_ADDR,ACCEL_XOUT_H_REG,I2C_MEMADD_SIZE_8BIT,recData,6,100);
HAL_Delay(50);
uint16_t dataConvert1,dataConvert2;
dataConvert1 = (uint16_t)(0x0000 | recData[0]) << 8;
dataConvert2 = (uint16_t)(0x0000 | recData[1]);
Accel_X_RAW = dataConvert1 | dataConvert2;
dataConvert1 = (uint16_t)(0x0000 | recData[2]) << 8;
dataConvert2 = (uint16_t)(0x0000 | recData[3]);
Accel_Y_RAW = dataConvert1 | dataConvert2;
dataConvert1 = (uint16_t)(0x0000 | recData[4]) << 8;
dataConvert2 = (uint16_t)(0x0000 | recData[5]);
Accel_Z_RAW = dataConvert1 | dataConvert2;
Ax = (uint16_t)(Accel_X_RAW / 16384);
Ay = (uint16_t)(Accel_Y_RAW / 16384);
Az = (uint16_t)(Accel_Z_RAW / 16384);
}
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_I2C3_Init();
MX_GPIO_Init();
MX_USB_DEVICE_Init();
MPU6050_Init();
while (1)
{
MPU6050_Read_Accel();
sprintf(buffer, "%d / ", Accel_X_RAW);
CDC_Transmit_FS((char*)buffer,10);
}
}

我已经在ATMEL Controler(Arduino(上做过了，它起作用了，但在STM32上没有。我正在尝试读取X轴的值，并使用USB CDC显示它。此代码为"Accel_X_RAW""变量设置一个介于0和65535之间的值。在Arduino中，对象停止时的参考值为32768，但如果没有移动，则使用STM32读取将保持在最大值(65535(。我不知道这个代码出了什么问题，我尝试了很多选项，但仍然不起作用。你能帮帮我吗。

Answer 1

根据MPU6050数据表，加速度和陀螺仪的16位值以带符号的2的补码形式返回(它检测+-g范围内的加速度值(。当您在无符号变量中接收到有符号的数据时，结果不是您所期望的。因此，将所有uint16_t数据类型替换为int16_t。

您获得65535值的原因；有符号int16_ t形式的-1的十六进制值是0xFFFF。但是，如果将其存储在uint16_t变量中，则它将被读取为65535。我假设静止时的默认加速度值是-1g。

#include <stdlib.h> /* For using memset */
#define MPU6050_ADDR 0xD0
#define SMPLRT_DIV_REG 0x19
#define GYRO_CONFIG_REG 0x1B
#define ACCEL_CONFIG_REG 0x1C
#define ACCEL_XOUT_H_REG 0x3B
#define TEMP_OUT_H_REG 0x41
#define GYRO_XOUT_H_REG 0x43
#define PWR_MGMT_1_REG 0x6B
#define WHO_AM_I_REG 0X75
int16_t Accel_X_RAW,Accel_Y_RAW,Accel_Z_RAW;
int16_t Ax,Ay,Az;
char buffer[10];
void MPU6050_Init(void)
{
uint8_t check, data;
HAL_I2C_Mem_Read(&hi2c3,MPU6050_ADDR,WHO_AM_I_REG,1,&check,1,100);
if(check == 104)
{
data = 0x07;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,SMPLRT_DIV_REG,1,&data,1,50);
HAL_Delay(50);
data = 0x00;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,ACCEL_CONFIG_REG,1,&data,1,50);
HAL_Delay(50);
data = 0x00;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,GYRO_CONFIG_REG,1,&data,1,50);
HAL_Delay(50);
data = 0;
HAL_I2C_Mem_Write(&hi2c3,MPU6050_ADDR,PWR_MGMT_1_REG,1,&data,1,50);
HAL_Delay(50);
}
}
void MPU6050_Read_Accel(void)
{
uint8_t recData[6];
//for(int i=0;i<6;i++) recData[i] = 0;
memset(recData, 0, sizeof(recData));
HAL_I2C_Mem_Read(&hi2c3,MPU6050_ADDR,ACCEL_XOUT_H_REG,I2C_MEMADD_SIZE_8BIT,recData,6,100);
HAL_Delay(50);
Accel_X_RAW = (int16_t)(recData[0] << 8 | recData[1]);
Accel_Y_RAW = (int16_t)(recData[2] << 8 | recData[3]);
Accel_Z_RAW = (int16_t)(recData[4] << 8 | recData[5]);
Ax = (int16_t)(Accel_X_RAW / 16384);
Ay = (int16_t)(Accel_Y_RAW / 16384);
Az = (int16_t)(Accel_Z_RAW / 16384);
}
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_I2C3_Init();
MX_GPIO_Init();
MX_USB_DEVICE_Init();
MPU6050_Init();
while (1)
{
MPU6050_Read_Accel();
sprintf(buffer, "%d / ", Accel_X_RAW);
CDC_Transmit_FS((char*)buffer,10);
}
}