BMI270 I2C with Raspberry Pi 3B+

Hello everyone,

I am a student and currently in my practical phase. I am trying to figure out what I am doing wrong when trying to read out the gyro data of the BMI270 for example.

I tried to compile the official Sensor API on Github but ran into error codes with COINES (i installed it) while compiling, so I used the latest version v2-53-2 which was without COINES, compiled it and ran into this error:
Error [-9] : Configuration load error. It occurs when failure observed while loading the configuration into the sensor

Which I couldn't figure out how to solve, so I started to write my own code as I really only want to read out the gyro data itself.
I connected the BMI270 via the quickconnect cable to the Raspberry Pi pins 1 (3.3 VDC), 3 (GPIO8 SDA1 (I2C)), 5 (GPIO 9 SCL1 (I2C)) and 9 (ground).

I am currently using the WiringPi library found here: http://wiringpi.com/
Essentially these are all the functions from the WiringPi libary for I2C:
int wiringPiI2CRead (int fd) ;
int wiringPiI2CWrite (int fd, int data) ;
int wiringPiI2CWriteReg8 (int fd, int reg, int data) ;
int wiringPiI2CWriteReg16 (int fd, int reg, int data) ;
int wiringPiI2CReadReg8 (int fd, int reg) ;
int wiringPiI2CReadReg16 (int fd, int reg) ;

There are also these functions which I wasn't able to use yet because I didn't know how I should give this function the dPin and cPin, though I saw that the cPin is 13 and dPin is 14 in the Datasheet.
uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order) ;
void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val) ;

In general I tried following the Quickstart Guide in the BMI270 Datasheet when writing my code.

Console logs of my code:

------START------

Device found!

DEVICE_ID: 3
CHIP_ID: 0x24
WRITING DATA ......... --> LAST DATA: 0xC1
Initialization status: 00000000 (Bit 0 = 1 --> OK)
7D before: 00001110
7D after: 00001110
40 before: 10101000
40 after: 10101000
42 before: 11101001
42 after: 11101001
7C before: 00000000
7C after: 00000010
rateX -8-Data_14: 0
rateX2-8-Data_15: 0
rateY -8-Data_16: 0
rateY2-8-Data_17: 0
rateZ -8-Data_18: 0
rateZ2-8-Data_19: 0
rateX -8-Data_14: 0
rateX2-8-Data_15: 0
rateY -8-Data_16: 0
rateY2-8-Data_17: 0
rateZ -8-Data_18: 0
rateZ2-8-Data_19: 0
rateX -8-Data_14: 0
rateX2-8-Data_15: 0
rateY -8-Data_16: 0
rateY2-8-Data_17: 0
rateZ -8-Data_18: 0
rateZ2-8-Data_19: 0

------END------

My burst_write function is essentially just using wiringPiI2CWriteReg8(..) in a for loop. Not sure if that would be the right way to do it when you want to upload the config file. But I believe it is probably not, because when I read out the Initialization status I alway receive a 0 for the Bit 0, which according to the Datasheet means its "not ok".

All in all I believe setting bits in the register works, but for some reason I can't read out data, probably because I am doing it wrong I believe. Also I tried out a very simple python code with the BMI160 and a compatible python Driver for it to test if the I2C even works and it seems to give me data there. I didn't try anything in python with the BMI270 yet because I wanted to keep it in C/C++. Maybe there could also be a problem with the WiringPi library I am using. Or I am just missing a specific register which I didn't set properly yet?
Or recommend me a different library which I could use or even post a code sample which works simliar to mine without using the Sensor API of Bosch.

Hopefully someone can help me bringt light into this. 🙂

Best Regards
Kevin

This is how my code looks at the moment:

#include <stdio.h>

#include <stdint.h>

#include <unistd.h>

#include <iostream>

#include <bitset>

#include <wiringPiI2C.h>

#include <wiringShift.h>

#include "bmi2_defs.h"

#define BIT_8 UINT8_C(8)

#define BIT_16 UINT8_C(16)

#define DATA_14 UINT8_C(0x12) // GYR_X(LSB) - gyr_x_7_0

#define DATA_15 UINT8_C(0x13) // GYR_X(MSB) - gyr_x_15_8

#define DATA_16 UINT8_C(0x14) // GYR_Y(LSB) - gyr_y_7_0

#define DATA_17 UINT8_C(0x15) // GYR_Y(MSB) - gyr_y_15_8

#define DATA_18 UINT8_C(0x16) // GYR_Z(LSB) - gyr_z_7_0

#define DATA_19 UINT8_C(0x17) // GYR_Z(MSB) - gyr_z_15_8

using std::bitset;

using std::cout;

using std::endl;

using std::hex;

using std::uppercase;

using std::string;

// 8192 elements - THIS CONFIG FILE WAS SHORTED FOR FORUMS POST

const uint8_t bmi270_config_file[] = { 0xc8, 0x2e, 0x00, ..., 0x2e, 0x00, 0xc1};

// -----------------------------------------------------------------------------------

void burst_write_reg(int fd, int reg, int array_len, const uint8_t *data, int format);

void burst_read_reg(int fd, int reg, int len, int format);

void configure_reg(int fd, int reg, int value, int format);

int main()

{

// --------------------------------------

// START - AREA

// --------------------------------------

cout << "\n\n------START------\n\n";

int fd = wiringPiI2CSetup(BMI2_I2C_PRIM_ADDR);

if (fd == -1)

{

cout << "ERROR: Device not found!\n\n";

return -1;

}

else

cout << "Device found!\n\n";

cout << "DEVICE_ID: " << fd << endl;

int chipID = wiringPiI2CReadReg8(fd, BMI2_CHIP_ID_ADDR);

cout << "CHIP_ID: 0x" << hex << chipID << endl;

// --------------------------------------

// INITIALIZATION - AREA

// --------------------------------------

// Reset the device

#if 0

configure_reg(fd, BMI2_CMD_REG_ADDR, BMI2_SOFT_RESET_CMD, BIT_8);

#endif

// Load config file

wiringPiI2CWriteReg8(fd, BMI2_PWR_CONF_ADDR, 0x00);

usleep(450);

wiringPiI2CWriteReg8(fd, BMI2_INIT_CTRL_ADDR, 0x00);

burst_write_reg(fd, BMI2_INIT_CTRL_ADDR, 8192, bmi270_config_file, BIT_8);

wiringPiI2CWriteReg8(fd, BMI2_INIT_CTRL_ADDR, 0x01);

// Check initialization status (Bit 0 = 1 --> OK)

bitset<8> binary_initialization(wiringPiI2CReadReg8(fd, BMI2_INTERNAL_STATUS_ADDR));

cout << "Initialization status: " << binary_initialization << "\t\t(Bit 0 = 1 --> OK)\n";

// --------------------------------------

// CONFIGURATION - AREA

// --------------------------------------

// Configuring the device for performance mode

// enable acquisiton of acceleration, gyroscope and temperature sensor data. disable the auxiliary interface.

configure_reg(fd, BMI2_PWR_CTRL_ADDR, 0x0E, BIT_8);

// enable the acc_filter_perf bit; set acc_bwp to normal mode; set acc_odr to 100 Hz

configure_reg(fd, BMI2_ACC_CONF_ADDR, 0xA8, BIT_8);

// enable the gyr_filter_perf bit; enable gyr_noise_perf bit; set gyr_bwp to normal mode; set gyr_odr to 200 Hz

configure_reg(fd, BMI2_GYR_CONF_ADDR, 0xE9, BIT_8);

// disable the adv_power_save bit; leave the fifo_self_wakeup enabled

configure_reg(fd, BMI2_PWR_CONF_ADDR, 0x02, BIT_8);

// --------------------------------------

// OUTPUT - AREA

// --------------------------------------

int LOOPS = 3;

for (int i = 0; i < LOOPS; i++)

{
int rateX = wiringPiI2CReadReg8(fd, DATA_14);

// rateY = -(~(int8_t)rateY + 1);

cout << "rateX -8-Data_14: " << rateX << endl;

int rateX2 = wiringPiI2CReadReg8(fd, DATA_15);

cout << "rateX2-8-Data_15: " << rateX2 << endl;

int rateY = wiringPiI2CReadReg8(fd, DATA_16);

cout << "rateY -8-Data_16: " << rateY << endl;

int rateY2 = wiringPiI2CReadReg8(fd, DATA_17);

cout << "rateY2-8-Data_17: " << rateY2 << endl;

int rateZ = wiringPiI2CReadReg8(fd, DATA_18);

cout << "rateZ -8-Data_18: " << rateZ << endl;

int rateZ2 = wiringPiI2CReadReg8(fd, DATA_19);

cout << "rateZ2-8-Data_19: " << rateZ2 << endl;

}

// --------------------------------------

// END - AREA

// --------------------------------------

cout << "\n\n------END------\n\n";

return 0;

}

// --------------------------------------

// FUNCTIONS - AREA

// --------------------------------------

// REMOVED FOR FORUMS POST