On FX2, with quad buffered EP2 bulk configured as IN
The TRM isn't clear if the empty/full signals are conveying state of a single
512 byte buffer or on all 4 buffers.
1) Does the Empty Flag means all 4 buffers are empty? Or just the active buffer?
2) Does the Full Flag mean all 4 buffers are full? Or just the active buffer?
The link below suggests the answer is "just the active buffer" for both questions. I just needed to confirm.
The external master typically monitors the ‘empty’ flag (EF) of OUT endpoints and the full (FF) flag of IN endpoints. If the Full Flag is asserted it indicates that no more FIFO buffers are available for the external master to write into. Similarly If the Empty Flag is asserted it indicates that no more FIFO buffers are available for the external master to read from.