Send UDP packet from w5500 to PC failed!


According below steps, i can’t send an UDP packet.

  1. Initialized W5500(set w5500 ip,port, host PC ip, port).
  2. Open w5500 upd socket.
  3. sendto() packet to host pc.
    the result :failed send out the packet. the register value of IINCHIP_READ( Sn_IR(s)) is timeout all the time.

until I received a packet from PC host using receivefrom(), w5500 can send udp packet to host pc using Sendto() successfully.

PC firewall is disable. antivirus software is closed.

Has anyone meet this issue?



Did you configure W5500 ip addess as well as gateway, subnet?
If you did, for analysing the timeout of udp, you shoud be captured the packet using wireshark program that is freeware.

Plz, post the captured file on here.

thank you.


Hi midnightcow,

Thanks your reply.

I checked my network config parameters, maybe my host ip and port info error.

Now my prototype can work normal.

Thanks & Best regards,



I’m glad to solve your problem.

Thank you.