sorry for confusion, after learning first time about smart covers I am still not sure why you mention it here (that’s why I got confused) Maybe because you abandoned any kind of I2C on any FP2 . Of course without SDK and some driver software this kind of hardware extension will not work out of the box . But this was clear from the first look on your scheme. However the FT311 with FP2 front USB client still is first choice for testing.