is it possible to have a OUT transfer (from host to device) to a large endpoint (2,4,6 or 8) with a size less of 512 byte?
You can send OUT transfer with bytes less than 512 bytes to any out endpoint.
I have endpoint 2 configured like OUT endpoint in automode with slave fifo double buffered. Size is 512 byte. When FX2 receive a packet of 512 byte from host it is commited and placed on fifo automatically, without cpu action.
If I send, for example, a packet of 200 byte, this packet is committed and placed on fifo in the same manner?
Yes, even if you send 512bytes or less than 512 bytes, it will be committed to peripheral domain.
In this case (after sending 200 or 512 bytes )If the external hasn't read the data from the buffer than you can send one more packet of 512 bytes or less.
If you try to send the third packet then it will be failed as buffers are full.