Are there any guidelines for using the Gigabit Ethernet MAC with the 1000BASE-X PCS/PMA interface on the ML300 board?
When using the GMAC with the 1000BASE-X PCS/PMA interface on the ML300 board, you need to consider the following:
- MDIO_IN input must be tied to '1' if unused as stated in the "MDIO Interface Signal Pinout" table of the data sheet.
- The Isolate bit in the PCS/PMA core must be set to '0' via the Host Interface of the GMAC. Otherwise, the GMAC is 'isolated' from the PCS/PMA and the MGT, and nothing will go in or out of the FPGA device if this bit is set. The isolate bit defaults on power-up to '1' as defined in the IEEE spec.
- If using Synplify, a /* synthesis syn_noclockbuf = 1 */ constraint is required to keep it from inferring a BUFG on clocks output from the GMAC.