05-26-2012 11:15 AM
Hi, I'm current using xc5vlx110-2ff1153 FPGA Chip.
I wan to upgrade my existing communication design from RS422 to Ethernet.
My existing design generate/receive some data in FPGA and sent/rx to/from a computer for decoding via RS422
I wan to upgrade this function to ethernet speed.
My hardware design does not have microblaze or power pc.
I have a M88E1111 PHY Chip.
1) Do I need any memory chip to implement the design?
2) Can the following structure work?
Current data generater (FPGA module) <-> MAC IP CORE <-> M88E1111<->Computer
3) Also can I confirm that the data rx from the MAC IP CORE is stripped of the pre-am, DA, DA ... Only left with the Data portion?
4) Which Ethernet IP Core should I use with xc5vlx110-2ff1153?
05-26-2012 03:20 PM
1) Whether you need memory really depends on how you want to use Ethernet. If you are thinking
of implementing a tcp stack, for instance you probably want memory as well as an embedded processor.
On the other hand, the MAC itself requires no external memory, and if your connection is point to point
you could "cheat" by using fixed addresses and possibly use UDP for a much simpler approach.
2) You data generator will need to packetize the data for Ethernet. UDP is probably the simplest
for data delivery.
3) The MAC IP core strips off the preamble, but you still get the MAC addresses, etc. You need to
pick out the data from the packet. If you use WireShark, you can see in its data window exactly
the data that the MAC IP core passes through.
4) Unfortunately the Virtex 5 parts without transceivers also have no hard TEMAC's. So you'll
need the full Ethernet MAC rather than just the wrapper. This MAC IP is not free. There may be
other third-party offerings as well as those from Xilinx.
Question for you: Are you planning to run the 88E1111 in tri-speed mode (10/100/1000) or
just pick one speed? The Ethernet MAC uses a lot of clock resources when using the
GMII interface in tri-speed mode. If you know the computer is always Gigabit capable,
then you can save resources by customizing the MAC for GigE only (or pick another speed).