1. Does billboard detect the alternate modes or the modes are pre-defined in its firmware?
ANS) Yes the Billboard detect the alternate modes and that matches with that comes from CCG2.
2. Can single Billboard serve multiple CCG2 ?
ANS) The question is not quite clear. In most of our designs we have used Billboard only with one CCG2. In one Notebook design we have two CCG2 with one controlling the upstream Type-C and the other downstream Type-C. In this case one Billboard is connected to both the controller but the Billboard function is applicable only for the upstream port, the down stream port is used only for firmware update.
3. Will CCG2 write back some data to Billboard?
ANS. No CCG2 doesn't write back to Billboard.