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Hi all, Problem: - Unable to access the magnetometer registers of MPU9150. Output: -What I am getting is 0xFF on reading every register (corresponding to magnetometer). On the other hand I am able to access the registers of the accelerometer and the gyroscope perfectly. I have initialized the system with i2c master mode disabled and i2c bypass mode enabled. Following is the code I have used to initialize the system:- single_byte_write(0x6B,0x01); single_byte_write(0x19,0x01); single_byte_write(0x1A,0x02); single_byte_write(0x1B,0x11); single_byte_write(0x1C,0x10); single_byte_write(0x6A,0x00); single_byte_write(0x37,0x02); (‘single_byte_write(address,data) writes the data byte to the register with ‘address’ to the slave address as 0x69’) I accessed the registers of accel. and gyro. as following:- single_byte_read(0x75,wia_mpu); which returns 0x68 which is correct as the who_i_am register. But when I tried to access the magnetometer registers as:- single_byte_read_compass(0x00,wia_compass); it returns 0xFF while it should return 0x48. In order to ensure that single_byte_read_compass()/single_byte_write_compass() works correctly I have used these functions with a change in slave address(from ‘0x0C’ to ‘0x69’)to access the registers of accel. and gyro. and it worked correctly. (The difference between ‘single_byte_read()’ and ‘single_byte_read_compass()’ is just that the former uses the slave address as ‘0x69’ while the later uses ‘0x0C’ as the slave address. I have also tried ‘0x0D’, ‘0x0E’ and ‘0x0F’ as the slave address but the output remained the same.) I have also ensured whether the MPU9150 is in pass-through mode. I have checked the output at the pins ‘ES_DA’ i.e. pin6 and the SDA i.e. pin24 with the help of oscilloscope which comes out to be exactly same, with by-pass mode enabled. With master-mode disabled and by-pass mode disabled the output at ‘ES_DA’ is zero always. I have also tried the same procedure as above with not just one but many MPU9150s but the output remained the same, thus most likely there is some problem with the code. Please help me figure it out.

Hello, I am attaching an Arduino example sketch to show how to read a magnetometer (HMC5883L) while MPU's DMP is active. This is only useful if you have your magnetometer attached to MPU's I2C internal aux lines, like many 10DOF boards do, and you want to use DMP. If you can, I believe it is always best to connect your magnetometer to your main I2C lines directly and you won't need this sketch. This sketch does NOT fuse DMP + magnetometer. You will have to do it by yourself in your host processor. I would only try to fuse magnetometer if it is going to be used outdoors, as electromagnetic interferences caused by electronics indoor make it quite difficult. Besides, the DMP's yaw measure is very good if you don't need much precision or long running times, in these cases you should fuse magnetometer + DMP. Please read sketch comments, as many things are explained there. Remember to put your MPU's address (0x68 or 0x69) and to set your interruption pin. Please give feedback, wheter it works or you have trouble with it. If people find it useful maybe Jeff can add it to the library once it is bugfree. Thank you MPU6050_DMP_mag.zip

Hi, I know that there are some eamples showing how to put magnetometer data into DMP. For example this one: http://www.i2cdevlib.com/forums/topic/111-arduino-example-sketch-to-read-magnetometer-while-dmp-is-on/ but it does not make any sensor fusion. I couldn't find any library which would make magnetometer fusion inside DMP. Does such library exist? Maybe code in this file MPU6050_9Axis_MotionApps41.h make DMP+magnetometer fusion? I couldn't find any tips in the code and right now I am not able to test it. So the question is: does such library exist or the only way to do this is to make own fiters (for example complementary filter)? Maybe there is some MPU9150 library that can be used with MPU6050+magnetometer?