ALTGX: Byte Ordering is disabled when Rate Match FIFO is enabled
I'm working on Cyclone IV ALTGX @ basic mode, x16, loopback and use Quartus 13.
I want to enable Byte Ordering. The issue is that when Rate Match FIFO is enabled, Quartus automatically disable the Byte Ordering. I do need Byte Ordering since data are coming in reverse byte order. 1. Why there is a relation between the two Byte Ordering and Rate Match FIFO ? 2. Is this limitation only in Cyclone IV or Quartus 13 ? 3. If I do want Rate Match FIFO is that mean I had to implement Byte Ordering on the Fabric ? Another Q regards to Rate Match FIFO and x16 mode, assuming stream is already byte ordered. Is there a guarantee that Rate Match FIFO will add/remove skip bytes in such it keep steam byte order (i.e., 2 bytes or 4 bytes) not to break the byte ordering ? Handbook mention only that Rate Match FIFO will remove SKP as long as there is at least one SKP in the stream; add up to 4 at most there is up to 5 SKP is the stream. thanks.