Hi,
Still struggling with the external I2C1 port. I have found if I disconnect the DS2482 I2C device board with 1.5K pullups for SDA and SCL lines to the VBAT and try an I2C program without the Circle OS I can get toggling on the I2C lines. From the datasheet for the DS2482, I calculated the 1.5K pullups to be ok. Is that really correct? Still looking for help to use the I2C1 port with the Circle OS also. Thanks!