Connecting Ethernet PHY via RMII seems like the way to go as there are less wires and less clocks from the PHY.
So did I think.. until I had this on my desk (Artix A200T fresh from oven):
Starting Vivado, click click click.. Exporting to SDK, click...
Starting lwIP based Echo Server. No Echo. No nothing.
Enabling all possible software debug settings..
Nothing.. Echo server starts and nothing after that.
Stepping back to simpler test, starting Xilinx peripheral test that does PHY loop-back. Connecting Artix to PC using USB Ethernet Adapter. Starting peripheral test. Link goes down. And does not come back. Connecting DSO to RJ45 to SMA break out board and what I see?
Continuous MLT-3 encoded transmit data-streams with no gaps alternating with about 2 seconds interval on RX and TX pairs!
Consulting TLK106 datasheet: MII loopback is available in MII mode.
So?
Consulting TLK106 datasheet again: MII loopback is available in MII mode.
MII or RMII? That is the question. I have read this before but I assumed that MII refers to MII or RMII..
Changing MII loopback enable code to PCS loopback. Peripheral test still does not complete. Do we transmit something at all? So the network adapter properties dialog has never displayed any packets form Artix. Ever.
I mod one of Xilinx examples (the ping requester) to send one packet in eternal loop. Starting the app - as soon as I do, windows starts sending megabytes per second. I press halt in debugger. Windows stop sending packets. All the time the properties pages shows 0 packets received.
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