我正在尝试使用STM32F303微控制器构建自平衡机器人，并且我正在使用MPU6050进行位置测量。使用I2C传输协议传输和接收数据。我以前有使用STM32F303并熟悉 I2C协议的经验，并查阅 MPU6050 ， STM32F303 的数据表以及我的一些在线资源使用ST Electronics提供的标准外设库构建代码。问题是我得到了读数但响应时间太慢了。平均而言，它应该消耗最大 2-3ms ，但这里耗费超过 400ms ，我完全无法弄明白。由于时间安排是这个项目的关键，因此我需要有关此问题的指南。我使用 Atollic 作为我的IDE，代码文件如下 MAIN.C
#include "stm32f30x.h"
#include "stm32f30x_gpio.h"
#include "stm32f30x_i2c.h"
#include "stm32f30x_rcc.h"
#include "stm32f30x_spi.h"
#include "stm32f30x_misc.h"
#include "math.h"
#include "mpu6050.h"
#define I2C_SDA_PIN GPIO_Pin_9 // PORTB
#define I2C_SCL_PIN GPIO_Pin_8 // PORTB
#define degconvert 57.2957786 // There are like 57 degrees in a radian.
MPU6050_errorstatus err;
static int i = 0;
float gyro_xdata;
float gyro_ydata;
float gyro_zdata;
float accel_xdata;
float accel_ydata;
float accel_zdata;
float roll;
float pitch;
void initializeGPIO();
void initializeI2C();
int main(void)
{
initializeGPIO();
initializeI2C();
err = MPU6050_Initialization();
// Getting Raw Values
err = MPU6050_Get_Gyro_Data(&gyro_xdata, &gyro_ydata, &gyro_zdata);
err = MPU6050_Get_Accel_Data(&accel_xdata, &accel_ydata, &accel_zdata);
// Calculate Pitch and Roll
roll = atan2f(accel_ydata, accel_zdata) * degconvert;
pitch = atan2f(-accel_xdata, accel_zdata) * degconvert;
while(1)
{
// Collect Raw Data from Sensor
err = MPU6050_Get_Gyro_Data(&gyro_xdata, &gyro_ydata, &gyro_zdata);
err = MPU6050_Get_Accel_Data(&accel_xdata, &accel_ydata, &accel_zdata);
// The next two lines calculate the orientation of the Accelerometer relative
// to the earth and convert the output of atan2 from Radians to Degrees
// We will use this data to correct any Cumulative errors in the Orientation
// that the gyroscope develops.
roll = atan2f(accel_ydata, accel_zdata) * degconvert;
pitch = atan2f(-accel_xdata, accel_zdata) * degconvert;
}
}
MPU6050.c
#include "mpu6050.h"
uint32_t MPU6050_Timeout = MPU6050_FLAG_TIMEOUT;
MPU6050_dataStruct dataStruct;
/* @brief Sets up MPU6050 internal clock and sensors sensitivity rate
* This function must be called before using the sensor!
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Initialization(void){
MPU6050_errorstatus errorstatus;
/* Set Clock source for the chip
* possible values @pwr_mngt_1
*/
errorstatus = MPU6050_Set_Clock(MPU6050_PLL_X_GYRO);
if(errorstatus != 0) return errorstatus;
/* Set Gyroscope's full scope range
* possible values @gyro_scale_range
*/
errorstatus = MPU6050_Gyro_Set_Range(MPU6050_GYRO_250);
if(errorstatus != 0) return errorstatus;
/* Set Accelerometer's full scope range
* possible values @accel_scale_range
*/
errorstatus = MPU6050_Accel_Set_Range(MPU6050_ACCEL_2g);
if(errorstatus != 0) return errorstatus;
return MPU6050_NO_ERROR;
}
/* @brief Test if chip is visible on I2C line
* Reads the WHO_AM_I register
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Test(void){
MPU6050_errorstatus errorstatus;
uint8_t tmp;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, WHO_AM_I, &tmp, 1);
if(tmp != (uint8_t)0x68){
return errorstatus;
}
return MPU6050_NO_ERROR;
}
/* @brief Get Gyroscope's full scale range
* Reads the GYRO_CONFIG register and returns the value of gyro's range
*
* @retval tmp - value of gyro's range
*/
uint8_t MPU6050_Gyro_Get_Range(void){
MPU6050_errorstatus errorstatus;
uint8_t tmp;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_CONFIG, &tmp, 1);
if(errorstatus != 0){
return 1;
}
else return tmp;
}
/* @brief Set Gyroscope's full scale range
* @param range - check @MPU6050_Gyro_Range
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Gyro_Set_Range(MPU6050_Gyro_Range range){
MPU6050_errorstatus errorstatus;
dataStruct.gyroMul = range;
errorstatus = MPU6050_Write((MPU6050_ADDRESS & 0x7f) << 1, GYRO_CONFIG, &range);
if(errorstatus != 0){
return errorstatus;
}
else return MPU6050_NO_ERROR;
}
/* @brief Get Accelerometer full scale range
* Reads the Accel_CONFIG register and returns the value of accelerometer's range
*
* @retval tmp - value of accelerometer's range
*/
uint8_t MPU6050_Accel_Get_Range(void){
MPU6050_errorstatus errorstatus;
uint8_t tmp;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_CONFIG, &tmp, 1);
if(errorstatus != 0){
return 1;
}
else return tmp;
}
/* @brief Set Accelerometer full scale range
* @param range - check @MPU6050_Accel_Range
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Accel_Set_Range(MPU6050_Accel_Range range){
MPU6050_errorstatus errorstatus;
dataStruct.accelMul = range;
errorstatus = MPU6050_Write((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_CONFIG, &range);
if(errorstatus != 0){
return errorstatus;
}
else return MPU6050_NO_ERROR;
}
/* @brief Set MPU6050 clock source
* @param clock - check @MPU6050_Clock_Select
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Set_Clock(MPU6050_Clock_Select clock){
MPU6050_errorstatus errorstatus;
errorstatus = MPU6050_Write((MPU6050_ADDRESS & 0x7f) << 1, PWR_MGMT_1, &clock);
if(errorstatus != 0){
return errorstatus;
}
else return MPU6050_NO_ERROR;
}
/* @brief Read MPU6050 temperature
* @retval temp_celsius - temperature in degrees celsius
*/
int16_t MPU6050_Get_Temperature(void){
MPU6050_errorstatus errorstatus;
uint8_t temp_low;
uint8_t temp_high;
int16_t temp;
int16_t temp_celsius;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, TEMP_OUT_L, &temp_low, 1);
if(errorstatus != 0){
return 1;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, TEMP_OUT_H, &temp_high, 1);
if(errorstatus != 0){
return 1;
}
temp = (uint16_t)(temp_high << 8 | temp_low);
temp_celsius = temp/340 + 36;
return temp_celsius;
}
/* @brief Get Gyroscope X,Y,Z raw data
*
* @param X - sensor roll on X axis
* @param Y - sensor pitch on Y axis
* @param Z - sensor jaw on Z axis
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Get_Gyro_Data_Raw(int16_t* X, int16_t* Y, int16_t* Z){
MPU6050_errorstatus errorstatus;
uint8_t xlow, xhigh, ylow, yhigh, zlow, zhigh;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_XOUT_L, &xlow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_XOUT_H, &xhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_YOUT_L, &ylow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_YOUT_H, &yhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_ZOUT_L, &zlow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, GYRO_ZOUT_H, &zhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
*X = (int16_t)(xhigh << 8 | xlow);
*Y = (int16_t)(yhigh << 8 | ylow);
*Z = (int16_t)(zhigh << 8 | zlow);
return MPU6050_NO_ERROR;
}
/* @brief Get Accelerometer X,Y,Z raw data
*
* @param X - sensor accel on X axis
* @param Y - sensor accel on Y axis
* @param Z - sensor accel on Z axis
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Get_Accel_Data_Raw(int16_t* X, int16_t* Y, int16_t* Z){
MPU6050_errorstatus errorstatus;
uint8_t xlow, xhigh, ylow, yhigh, zlow, zhigh;
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_XOUT_L, &xlow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_XOUT_H, &xhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_YOUT_L, &ylow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_YOUT_H, &yhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_ZOUT_L, &zlow, 1);
if(errorstatus != 0){
return errorstatus;
}
errorstatus = MPU6050_Read((MPU6050_ADDRESS & 0x7f) << 1, ACCEL_ZOUT_H, &zhigh, 1);
if(errorstatus != 0){
return errorstatus;
}
*X = (int16_t)(xhigh << 8 | xlow);
*Y = (int16_t)(yhigh << 8 | ylow);
*Z = (int16_t)(zhigh << 8 | zlow);
return MPU6050_NO_ERROR;
}
/* @brief Get Gyroscope X,Y,Z calculated data
*
* @param X - sensor roll on X axis
* @param Y - sensor pitch on Y axis
* @param Z - sensor jaw on Z axis
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Get_Gyro_Data(float* X, float* Y, float* Z){
MPU6050_errorstatus errorstatus;
float mult;
int16_t gyro_x, gyro_y, gyro_z;
errorstatus = MPU6050_Get_Gyro_Data_Raw(&gyro_x, &gyro_y, &gyro_z);
if(dataStruct.gyroMul == MPU6050_GYRO_250){
mult = (float)(1/MPU6050_GYRO_RANGE_250);
}
else if(dataStruct.gyroMul == MPU6050_GYRO_500){
mult = (float)(1/MPU6050_GYRO_RANGE_500);
}
else if(dataStruct.gyroMul == MPU6050_GYRO_1000){
mult = (float)(1/MPU6050_GYRO_RANGE_1000);
}
else mult = (float)(1/MPU6050_GYRO_RANGE_2000);
*X = (float)(gyro_x*mult);
*Y = (float)(gyro_y*mult);
*Z = (float)(gyro_z*mult);
return MPU6050_NO_ERROR;
}
/* @brief Get Accelerometer X,Y,Z calculated data
*
* @param X - sensor accel on X axis
* @param Y - sensor accel on Y axis
* @param Z - sensor accel on Z axis
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Get_Accel_Data(float* X, float* Y, float* Z){
MPU6050_errorstatus errorstatus;
float mult;
int16_t accel_x, accel_y, accel_z;
errorstatus = MPU6050_Get_Accel_Data_Raw(&accel_x, &accel_y, &accel_z);
if(dataStruct.accelMul == MPU6050_ACCEL_2g){
mult = (float)(1/MPU6050_ACCEL_RANGE_2g);
}
else if(dataStruct.accelMul == MPU6050_ACCEL_2g){
mult = (float)(1/MPU6050_ACCEL_RANGE_4g);
}
else if(dataStruct.accelMul == MPU6050_ACCEL_2g){
mult = (float)(1/MPU6050_ACCEL_RANGE_8g);
}
else mult = (float)(1/MPU6050_ACCEL_RANGE_16g);
*X = (float)(accel_x*mult);
*Y = (float)(accel_y*mult);
*Z = (float)(accel_z*mult);
return MPU6050_NO_ERROR;
}
/* @brief Reads bytes from MPU6050
*
* @param SlaveAddr - Slave I2C address
* @param RegAddr - register address
* @param pBuffer - buffer to write to
* @ param NumByteToRead - number of bytes to read
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Read(uint8_t SlaveAddr, uint8_t RegAddr, uint8_t* pBuffer, uint16_t NumByteToRead)
{
/* Test if SDA line busy */
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) != RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_TransferHandling(I2C1, SlaveAddr, 1, I2C_SoftEnd_Mode, I2C_Generate_Start_Write);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
if(NumByteToRead>1)
RegAddr |= 0x80;
I2C_SendData(I2C1, (uint8_t)RegAddr);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TC) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_TX_ERROR;
}
I2C_TransferHandling(I2C1, SlaveAddr, NumByteToRead, I2C_AutoEnd_Mode, I2C_Generate_Start_Read);
while (NumByteToRead)
{
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_RX_ERROR;
}
*pBuffer = I2C_ReceiveData(I2C1);
pBuffer++;
NumByteToRead--;
}
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_ClearFlag(I2C1, I2C_FLAG_STOPF);
return MPU6050_NO_ERROR;
}
/* @brief Writes bytes to MPU6050
*
* @param SlaveAddr - Slave I2C address
* @param RegAddr - register address
* @param pBuffer - buffer to write from
*
* @retval @MPU6050_errorstatus
*/
MPU6050_errorstatus MPU6050_Write(uint8_t SlaveAddr, uint8_t RegAddr, uint8_t* pBuffer)
{
/* Test if SDA line busy */
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) != RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_TransferHandling(I2C1, SlaveAddr, 1, I2C_Reload_Mode, I2C_Generate_Start_Write);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_SendData(I2C1, (uint8_t) RegAddr);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TCR) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_TransferHandling(I2C1, SlaveAddr, 1, I2C_AutoEnd_Mode, I2C_No_StartStop);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_SendData(I2C1, *pBuffer);
MPU6050_Timeout = MPU6050_LONG_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF) == RESET)
{
if((MPU6050_Timeout--) == 0) return MPU6050_I2C_ERROR;
}
I2C_ClearFlag(I2C1, I2C_FLAG_STOPF);
return MPU6050_NO_ERROR;
}
答案 0 :(得分：0)
我找到了问题的答案。当我试图调试它时，发现I2C协议的时钟频率非常低，大约 1 Khz ，因为它应该在 4 Khz 的范围内正确的操作和性能效率。我试图查阅数据表，我发现问题出在I2C模块的定时寄存器上。在I2C定时寄存器中，最后4位专用于时钟频率预分频器，在我的情况下它被设置为满，因此频率被分频到最大程度。所以在I2C模块的初始化段
void initializeI2C(){
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
I2C_InitTypeDef I2C_InitStructure;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_OwnAddress1 = 0;
I2C_InitStructure.I2C_AnalogFilter = I2C_AnalogFilter_Enable;
I2C_InitStructure.I2C_DigitalFilter = 0x00;
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_Timing = 0xF062121F;
I2C_Init(I2C1, &I2C_InitStructure);
I2C_Cmd(I2C1, ENABLE);
}
我将I2C_Timing寄存器的值更改为0x0062121F并恢复了I2C的时钟频率，因此我能够获得几乎 4 ms的最大采样时间
I2C_InitStructure.I2C_Timing = 0x0062121F;