STM32F103C8T6 软件模拟I2C 连接 MPU9250 磁力计 - 代码示例

{"title":"STM32F103C8T6 软件模拟I2C 连接 MPU9250 磁力计 - 代码示例","description":"本示例代码演示了如何在 STM32F103C8T6 上使用软件模拟 I2C 协议连接 MPU9250 磁力计，并配置其寄存器和读取磁力计数据。","keywords":"STM32F103C8T6, MPU9250, 磁力计, I2C, 软件模拟, 寄存器配置, 代码示例","content":"#include "stm32f10x.h"

#define SDA_PIN GPIO_Pin_15 #define SDA_PORT GPIOB #define SCL_PIN GPIO_Pin_14 #define SCL_PORT GPIOB #define INT_PIN GPIO_Pin_7 #define INT_PORT GPIOB

#define MPU9250_ADDRESS 0x68 #define MAG_ADDRESS 0x0C

#define I2C_DELAY 5

void I2C_Start(void) { GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = SCL_PIN;
GPIO_Init(SCL_PORT, &GPIO_InitStructure);

GPIO_SetBits(SDA_PORT, SDA_PIN);
GPIO_SetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

GPIO_ResetBits(SDA_PORT, SDA_PIN);
delay(I2C_DELAY);

GPIO_ResetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

}

void I2C_Stop(void) { GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

GPIO_SetBits(SDA_PORT, SDA_PIN);
GPIO_SetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

GPIO_ResetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

GPIO_SetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

GPIO_SetBits(SDA_PORT, SDA_PIN);
delay(I2C_DELAY);

}

void I2C_WriteByte(uint8_t data) { GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

for (int i = 0; i < 8; i++)
{
    if (data & 0x80)
    {
        GPIO_SetBits(SDA_PORT, SDA_PIN);
    }
    else
    {
        GPIO_ResetBits(SDA_PORT, SDA_PIN);
    }
    
    data = data << 1;
    delay(I2C_DELAY);
    
    GPIO_SetBits(SCL_PORT, SCL_PIN);
    delay(I2C_DELAY);
    GPIO_ResetBits(SCL_PORT, SCL_PIN);
    delay(I2C_DELAY);
}

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

delay(I2C_DELAY);

GPIO_SetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);
uint8_t ack = GPIO_ReadInputDataBit(SDA_PORT, SDA_PIN);
GPIO_ResetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

}

uint8_t I2C_ReadByte(uint8_t ack) { GPIO_InitTypeDef GPIO_InitStructure; uint8_t data = 0;

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

for (int i = 0; i < 8; i++)
{
    delay(I2C_DELAY);
    GPIO_SetBits(SCL_PORT, SCL_PIN);
    delay(I2C_DELAY);
    data = data << 1;
    data |= GPIO_ReadInputDataBit(SDA_PORT, SDA_PIN);
    GPIO_ResetBits(SCL_PORT, SCL_PIN);
    delay(I2C_DELAY);
}

GPIO_InitStructure.GPIO_Pin = SDA_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(SDA_PORT, &GPIO_InitStructure);

if (ack)
{
    GPIO_ResetBits(SDA_PORT, SDA_PIN);
}
else
{
    GPIO_SetBits(SDA_PORT, SDA_PIN);
}

GPIO_SetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);
GPIO_ResetBits(SCL_PORT, SCL_PIN);
delay(I2C_DELAY);

return data;

}

void MPU9250_WriteRegister(uint8_t reg, uint8_t value) { I2C_Start(); I2C_WriteByte(MPU9250_ADDRESS); I2C_WriteByte(reg); I2C_WriteByte(value); I2C_Stop(); }

uint8_t MPU9250_ReadRegister(uint8_t reg) { uint8_t value; I2C_Start(); I2C_WriteByte(MPU9250_ADDRESS); I2C_WriteByte(reg); I2C_Start(); I2C_WriteByte(MPU9250_ADDRESS | 0x01); value = I2C_ReadByte(0); I2C_Stop(); return value; }

void MPU9250_ConfigMag() { MPU9250_WriteRegister(0x6B, 0x80); // Reset MPU9250 delay(100); MPU9250_WriteRegister(0x6B, 0x01); // Clock Source MPU9250_WriteRegister(0x68, 0x07); // Enable Accel and Gyro MPU9250_WriteRegister(0x1A, 0x00); // Disable FSYNC and set 260 Hz Acc filter bandwidth MPU9250_WriteRegister(0x1B, 0x18); // Set Gyro Full Scale Range to ±2000deg/s MPU9250_WriteRegister(0x1C, 0x08); // Set Accel Full Scale Range to ±4g MPU9250_WriteRegister(0x23, 0x78); // Set Accel and Gyro DLPF to 184Hz MPU9250_WriteRegister(0x37, 0x02); // Enable bypass mode for magnetometer MPU9250_WriteRegister(0x6A, 0x00); // Clear Sleep Mode bit (6), enable all sensors delay(100); MPU9250_WriteRegister(0x37, 0x00); // Enable I2C Master Mode MPU9250_WriteRegister(0x6A, 0x20); // Enable the I2C Master for magnetometer reads MPU9250_WriteRegister(0x24, 0x0D); // Set the sample rate to 100Hz (10ms) MPU9250_WriteRegister(0x25, 0x09); // Set the sample rate divider to 9 for a 100Hz update rate MPU9250_WriteRegister(0x26, 0x06); // Set the compass update rate to 100Hz MPU9250_WriteRegister(0x27, 0x40); // Enable continuous reading at 100Hz MPU9250_WriteRegister(0x28, 0x06); // Enable 16-bit compass resolution delay(100); }

void MPU9250_ReadMagData(int16_t* magData) { I2C_Start(); I2C_WriteByte(MPU9250_ADDRESS); I2C_WriteByte(0x49); // Start read at register 0x49 I2C_Start(); I2C_WriteByte(MAG_ADDRESS | 0x01);

uint8_t xlo = I2C_ReadByte(1);
uint8_t xhi = I2C_ReadByte(1);
uint8_t ylo = I2C_ReadByte(1);
uint8_t yhi = I2C_ReadByte(1);
uint8_t zlo = I2C_ReadByte(1);
uint8_t zhi = I2C_ReadByte(0);

I2C_Stop();

magData[0] = (int16_t)((int16_t)xhi << 8 | xlo);
magData[1] = (int16_t)((int16_t)yhi << 8 | ylo);
magData[2] = (int16_t)((int16_t)zhi << 8 | zlo);

}

int main(void) { // 初始化GPIO和延时函数 // ...

// 配置MPU9250磁力计寄存器
MPU9250_ConfigMag();

while (1)
{
    int16_t magData[3];
    MPU9250_ReadMagData(magData);
    
    // 使用磁力计数据进行操作
    // ...
}

}

请注意，以上代码仅提供了一个软件模拟I2C的示例，并且假设您已经实现了delay()函数来提供延时功能。在实际使用中，您可能还需要根据自己的要求进行适当的修改和调整。