[usb] USB protocol questions

[Rudolf Usselmann <rudi@asics.ws>]

I have a few USB protocol questions. I would appreciate references
to the specification with your answers !

1) When operating in FS mode, PING tokens are not allowed.
   a) Should the function report PING tokens to it's controller?
   b) Should it reply to PING just as would in HS mode?
   c) Should it just ignore PING in FS mode?

2) When the function received an IN token, and sends DATA back
   to the host, the host will reply with an ACK if it accepted
   the data.
   a) What is the time-out period in which the host has to reply?
   b) If the host did not reply, what should the function do?
   c) If the ACK from the host becomes corrupt and the function
      ignores it, how should it proceed?

3) When a function receives an out token, the next packet will
   be a DATA packet.
   a) What is the time-out period for waiting for the data packet?

Thanks a lot !
rudi