--- title: "W5500 / W6100 Interrupt reason" url: "https://maker.wiznet.io/forum/15646" markdown_url: "https://maker.wiznet.io/forum/15646/md" type: "Forum topic" category: "Ethernet Chips" author: "JavorWM" created: "2025-03-18T22:03:52+09:00" last_activity: "2025-03-28T14:35:41+09:00" language: "en" tags: ["STM32"] views: 5 replies: 2 source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)" --- # W5500 / W6100 Interrupt reason ## Question Asked by JavorWM on 2025-03-18 in Ethernet Chips. Hello. I test W5500 and W6100 with interrupt with the official library. I have a listening socket (in my case socket 3) on a port. Everything works fine except, when I enter the interrupt handler, I don't know the reason causing the interrupt, the interrupt source (result from function wizchip_getinterrupt()) has a value of 0x0800, which corresponds to IK_SOCK_3 (1 << 11) in wizchip_conf.h. How can I get the reason for the interrupt, i.e. client connected, client sent packet, client disconnected, etc... In W5100 documentation it's said that read interrupt value is 1 << 2, which is reserved for W5500. I need to get all the states when client connects. Also another problem: when client disconnects, it cannot connect anymore. Do I have to to initialize server socket again after client disconnects? Thanks in advance. Regards, Javor ## Replies ### Reply 1 by JavorWM, 2025-03-19 After server closes client socket connection, for example using close(3), Sn_IR_DISCON is never called. How can this be handled? ### Reply 2 by louis_m, 2025-03-28 Fetches and processes all state when a client connects. If you check the attached loopback example code, it recreates the socket in the SOCK_CLOSED state. --- Source: https://maker.wiznet.io/forum/15646