Mpu9250 and bme280 circuit for library

stowp · January 31, 2021, 2:49am

Hi.

I have found the following library on internet:

on which pins should I connect sda, sda and int to connect a mpu9250 and bme280 to a stm32f103?

Tanks!

Marcelo.

matsujirushi · February 2, 2021, 6:51am

Hi @stowp ,
It looks like the library can run on Arduino Pro Mini 3.3V 8MHz or Teensy 3.1.

github.com

kriswiner/MPU9250/blob/master/MPU9250_BMP280_BasicAHRS_t3.ino#L10


/* MPU9250_MS5637_t3 Basic Example Code
 by: Kris Winer
 date: April 1, 2014
 license: Beerware - Use this code however you'd like. If you 
 find it useful you can buy me a beer some time.
 
 Demonstrate basic MPU-9250 functionality including parameterizing the register addresses, initializing the sensor, 
 getting properly scaled accelerometer, gyroscope, and magnetometer data out. Added display functions to 
 allow display to on breadboard monitor. Addition of 9 DoF sensor fusion using open source Madgwick and 
 Mahony filter algorithms. Sketch runs on the 3.3 V 8 MHz Pro Mini and the Teensy 3.1.
 
 This sketch is intended specifically for the MPU9250+BMP280 Add-on shield for the Teensy 3.1.
 It uses SDA/SCL on pins 17/16, respectively, and it uses the Teensy 3.1-specific Wire library i2c_t3.h.
 The MS5637 is a simple but high resolution pressure sensor, which can be used in its high resolution
 mode but with power consumption of 20 microAmp, or in a lower resolution mode with power consumption of
 only 1 microAmp. The choice will depend on the application.
 
 SDA and SCL should have external pull-up resistors (to 3.3V).
 4K7 resistors are on the MPU9250+MS5637 breakout board.

I think we can use Arduino compatible board, but I haven’t checked yet.

github.com

kriswiner/MPU9250/blob/master/MPU9250_BMP280_BasicAHRS_t3.ino#L29


4K7 resistors are on the MPU9250+MS5637 breakout board.
Hardware setup:
MPU9250 Breakout --------- Arduino
VDD ---------------------- 3.3V
VDDI --------------------- 3.3V
SDA ----------------------- A4
SCL ----------------------- A5
GND ---------------------- GND
Note: The MPU9250 is an I2C sensor and uses the Arduino Wire library. 
Because the sensor is not 5V tolerant, we are using a 3.3 V 8 MHz Pro Mini or a 3.3 V Teensy 3.1.
We have disabled the internal pull-ups used by the Wire library in the Wire.h/twi.c utility file.
We are also using the 400 kHz fast I2C mode by setting the TWI_FREQ  to 400000L /twi.h utility file.
*/
//#include "Wire.h"   
#include <i2c_t3.h>
#include <SPI.h>
// See also MPU-9250 Register Map and Descriptions, Revision 4.0, RM-MPU-9250A-00, Rev. 1.4, 9/9/2013 for registers not listed in 
// above document; the MPU9250 and MPU9150 are virtually identical but the latter has a different register map