I am using a CY7C65215A as a USB - I2C bridge acting as the I2C master. If I power my system on without USB connected to the 215A, the 215A holds my I2C lines low.
After I connect USB to the 215A, I see some activity on the I2C lines for a few seconds (driven by 215A), and then it lets go of the lines and they are pulled high. After the lines are pulled high, I can disconnect the USB from the system and the I2C lines are still inactive (pulled high).
Any thoughts on why this is happening?
See my schematic below. There are 2 I2C slave devices: an FPGA and a TCA9406 I2C level shifter, and has a 10k ohm pullup resistor.
I have built a small evaluation board with the same configuration on the 215A and I2C pullups, but no I2C slave on the bus, and the 215A exhibits the same behavior.
