Notes for reading the LXT975 Datasheet: General points to keep in mind while you are reading: 1. The datasheet is written for two components, the LXT974 and LXT975. The Calinx board has the 975. 2. The version of Ethernet that we have in the lab is 100baseT. This refers to 100 Mbps (million bits per second) line speed. The particular one we have is 100baseTX. The X refers to transmission over a twisted pair of wires. 3. The MII interfaces have both a control/status part and a data part. We will use only the data part of each MII interface. Control over the chip will be achieved using the "Hardware Control Interface Signals", see table 8. 4. Because we use a switched Ethernet in the lab, our PHY chips will never see any contention or collisions on the network wires. Therefore, all the discussion in the datasheet about collisions is not relevent. Read from the beginning of the Datasheet, up to and including section 2.5. Look at figure 26. I recommend that you, at least, look over the rest of the datasheet.