Coral Dev Board Mini i2C connect to Adafruit Motor Shield V2

Question

Anyone have any success connecting the Coral Dev Board Mini to Adafruit's Motor Shield V2 (AMS) with I2C?

My first solution was to use the only 3 PWM on the Dev Mini to control the speed and direction of a motor, but i need two motors.

So decided to go the I2C route coupled with Adafruit's Motor Shield V2.

I've connected the following pins between the board and shield

Mini 5V -> AMS Vin
Mini GND -> AMS GND
Mini SDA (pin 3) -> AMS SDA pin
Mini SCL (pin 5) -> AMS SCL pin

On the mini the SDA/SCL pins 3 & 5 are associated with device path /dev/i2c-3

sudo i2cdetect -y 3
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --       

and I should be seeing 0x60.

The default Mini pin states are

HIGH (4.7K pull-up) 

Any ideas?

Or Any thoughts on another solution to control the speed and direction of two motors?

Answer 1

I don't know the Adadfruit motor driver, but if you connect +5V to it's Vin it might well pull up the I2C lines to this voltage which might not be compatible with the 3.3V the mini dev uses. Have you checked this?

I have tried something similar, but with the SparkFun Auto pHAT (which does 3.3V <-> 5V conversion on the I2C bus). I could not get I2C working between the Auto pHat and the dev board mini. Maybe something in the I2C implementation of the mini is not working out of the box. I could control the Auto pHat with a (3.3V) ESP32 without problems.

I have also developed my own motor driver which is controlled by I2C and the prototype works well with the ESP32, I have not yet tried it with the the dev board mini. I'll give it a try and let you know.