1G eth UDP / IP Stack

I have a few questions about synchronization between tx_clk and rx_clk:

1. arp_req_req.lookup_req is launched by tx_clk in IPv4_tx.vhd, and it only keeps for one tx_clk cycle. arp_req_req.lookup_req is latched by rx_clk in arp_req.vhd, i'm not sure if this signal can be correctly latched since tx_clk and rx_clk are asynchronous.

2. This is a part of arp_sync.vhd:
   case ip_entry_state is when IDLE => if arp_nwk_req.req = '1' then ip_entry_reg <= arp_nwk_req.ip; ip_entry_state <= HOLD1; else ip_entry_reg <= ip_entry_reg; ip_entry_state <= IDLE; end if;

   Similarly, arp_nwk_req is launched by rx_clk, and latched by tx_clk. when arp_nwk_req.req = '1', arp_nwk_req.ip may not be valid for rx_clk.

You are correct. This stack has only been tested with synchronised rx & tx clocks.

If you can make some changes, test them, and email to me, then I will post an update to the stack.

OK, I will email you later with the modified vhdl

Thanks