ROB-16328 I2C Mystery Address

Robotics
1

I recently purchased a ROB-16328 Auto pHAT board to use to build a small robotic platform for my son to play with. I’m using a Jetson Nano as the main processor and connecting through the raspberry pi header.

I’m able to successfully query the FIDs for the IMU and the motor driver using the python smbus library.

However when I probe the I2C bus using i2cdetect I do not see the encoder reader at address 0x73 as expected and instead there is something located at address 0x70. The device at address 0x70 does not return the expected FID (0x5C according to the Qwiic Twist register map). I put a scope on the I2C bus and the data looks pretty clean.

Any insight would be greatly appreciated. Thanks in advance.

Here is the output of the i2cdetect :

user@user:~$ i2cdetect -y -r 1

0 1 2 3 4 5 6 7 8 9 a b c d e f

00: – – – – – – – – – – – – –

10: – – – – – – – – – – – – – – – –

20: – – – – – – – – – – – – – – – –

30: – – – – – – – – – – – – – – – –

40: 40 – – – – – – – – – – – – – – –

50: – – – – – – – – – – – – – 5d – –

60: – – – – – – – – – 69 – – – – – –

70: 70 – – – – – – –

2

Your Auto pHAT is showing on the correct I2C but your other items are on different addresses, correct?

3

I purchased the sparkfun 9DoF IMU (ICM20948 9 DoF IMU Breakout) as well aa Raspberry Pi 4 model B board. I installed lineageOS on the raspberry. I installed the camera modul v2. the camera is working but imu is not. I also purchaed Qwiic SHIM Kitwith the same IMU and using it on the i2c bus. The IMU works on the python driver supplied by your company but it doesn’t seem to be recognized when running programs that utilize an IMU