Can't find I2C slave with GPY in Pyscan

[Justin Forgue]

I have an Adafruit Feather M4 express setup as an I2C slave device with 4.7K pull up resistors on both SCL & SDA. I know that Feather is properly functioning because I wrote to it over I2C with another Feather setup as a master.

My GPY, with firmware 1.20.2.r6, is in a Pyscan board and according to the Pyscan pinout I am using pins P21 for SCL and pin P22 for SDA.

When I scan I2C the GPY comes up empty:

from machine import I2C

i2c = I2C(0, pins=('P21', 'P22'))
i2c.init(I2C.MASTER, baudrate=400000)
print(i2c.scan())

I have tried every baudrate from 1 to 500000 with P21 & P22 as well as P9 & P10, but still no luck.

Did I miss something here?