betwys1

The Due used with the MPU6050 needs minor mods, as follows: PROBLEM: Compile error MPU6050_DMP6.ino: In function 'void setup()': MPU6050_DMP6:165: error: 'TWBR' was not declared in this scope ANSWER: Amend a line of the I2C code as follows: #if I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE Wire.begin(); // TWBR = 24; // 400kHz I2C clock (200kHz if CPU is 8MHz) commented out for due R3 <<<commented out Wire.setClock(400000); // 400kHz I2C clock. Comment this line if having compilation difficultie <<<< added - speed setting ---------------------------------------------------------------------- PROBLEM: No data returned from FIFO. ANSWER: The correct interrupt signal on the DUE is "RX0 < 0" in other words, pin zero. Wire this to INT on the MPU6050 ----------------------------------------------------------------------------------- PROBLEM: The serial monitor does not scroll yaw/pitch/roll results until four keyboard entries are sent to flush the FIFO. ANSWER Initialize with four inputs (not yet executed). ------------------------------------------------------------------------------- PROBLEM: Want to run multiple MPU6050 etc.... ANSWER: rig a digital output wire to each MPU6050 (or other compatible device) address zero Select one digital output to HIGH to transfer data between a specific MPU6050 and the DUE in turn with the I2C library set to an address with bit zero HIGH Here is the code passage: // class default I2C address is 0x68 // specific I2C addresses may be passed as a parameter here // AD0 low = 0x68 (default for SparkFun breakout and InvenSense evaluation board) // AD0 high = 0x69 MPU6050 mpu; //MPU6050 mpu(0x69); // <-- use for AD0 high <<<< ACTIVATE THIS LINE ---------------------------------------------------------------------------------------------- PROBLEM: Values drift with time ANSWER: It's worth noting that on a first drift test of my DUE & MPU6050 & MPU6050_DMP6 sketch, the initial values of less than 1 degree each axis had changed to -147.5, -1.07, 0.91 nearly ten hours later. This seems to be a phenomenally low drift rate when stationary. -------------------------------------------------------------- Brian Whatcott

Fleshing out the responses to this desire: if four digital outputs are wired; one to each MPU 6050 address bit, and if the I2C code is set to address the bit high, then the Due selects the desired MPU6050 with its address bit high, transfers data, then resets that MPU6050's address bit to low, in favor of the next MPU6050.