Arty A7 LWIP Echo Server Example Doesn't Respond to ARP

[jmckinney]

I'm trying to standup an Arty A7 100. I'm using Vivado/Vitus 2022.1. I followed the instructions for the LWIP Echo Server. In Putty,  I can see:

-----lwIP TCP echo server ------
TCP packets sent to port 6001 will be echoed back
link speed: 100
DHCP Timeout
Configuring default IP of 10.48.30.104
Board IP: 10.48.30.104
Netmask : 255.255.255.0
Gateway : 10.48.30.1
Start Application
TCP echo server started @ port 7

 But I am un able to open a telnet session. Pinging it doesn't work. So I try to manually arp it via:

user@host:~$ sudo arp -v 10.48.30.104
Address                  HWtype  HWaddress           Flags Mask            Iface
10.48.30.104                     (incomplete)                              eno1
Entries: 22	Skipped: 21	Found: 1

 And it appears I'm getting no arp back. So I run a wireshark capture, while pinging, and I can see the ARP requests go out, but nothing coming back.

Looking at the board, on powerup in JTAG programming mode (so before it's configured with my bitstream), The Left RJ45 LED is on continuously. When I program my bitstream it turns off and stays off.

It may be noteable that I had to turn off link speed autonegotiation in the BSP in Vitis, to get to/past the "link speed: 100" line in the terminal output above.

 

Has anyone else had to overcome this problem?

Edited February 28 by jmckinney
Added details

[jmckinney]

turns out my eth_ref_clk wasn't set to 25MHz. Although I'm sure I set it to that.....(Looking at You Vivado!)