TCP connection only possible with a 2-4 sec delay between init and socket programming

Question

Hi all, I am busy programming the wiz550io as a TCP client to communicate with a server. Unfortunately i ran into some problems connecting to the server. Every time it runs the ‘connect()’ function it returns a time out error. While debugging the code i learned that establishing a connection with the server succesfully was only possible if a 3 - 4 sec delay was inserted before any of the socket programming commands. without this delay it goes straight to the time-out. In other topics i saw that it was due to the status of link of the PHY that the module wasn’t ready to set-up a connection yet. I tried implementing that by polling bit 0 of the PHYCFGR register, but without any luck… I’ll post my code here: retVal = init_spi(); if (STATUS_FAIL == retVal){ while(1); } init_w5500(); init_network(&pnetinfo); // __delay_cycles(2000000); <-- This is where i inserted the delay to make the connect() function work. while(getPHYCFGR() & PHYCFGR_LNK_ON); // PHYCFGR_LNK_ON (1<<0) mysock = socket(socketNum, Sn_MR_TCP, 5000, 0x00); if(mysock != socketNum) { while(1); } retVal = connect(mysock, addr, PORT_TCPC); if(retVal < 0) { while(1); } retVal = send(mysock, GREETING_MSG, strlen(GREETING_MSG)); if(retVal < 0) { while(1); } retVal = close(mysock); if(retVal < 0) { while(1); } while(1); As you can see it’s just a very simple code to open a socket, connect, send a message and lastly close the connection. What i also checked for were the packets send over the network through wireshark. The first picture posted is the code without the delay, where the connect() returns time out. The second shows a succesfull connection. 36%20PM2810×778 466 KB 57%20PM2810×580 195 KB For clarification, the BelkinIn is the USB-C to ethernet adapter i use to connect to the module. This device has been given the IP address where the Wiz550io module is looking for. The ARP message does get send out, but doesn’t get any response back, so maybe it’s something else than the module? Or maybe the network of the wiz550io hasn’t fully initialized yet, so it’s impossible for the host to send back a response? I hope someone can help me with this problem. Cheers, Caspar

becky · Answer

Caspar: while(getPHYCFGR() & PHYCFGR_LNK_ON); // PHYCFGR_LNK_ON (1<<0) I think you have to fix it such as below: while(!(getPHYCFGR() & PHYCFGR_LNK_ON));

becky · Answer

In the first packet, the W5500 sent an arp request. But belkin did not give an arp response. If the w5500 does not receive an arp response, it retransmits every 200ms. However, no retransmission is seen in the first packet. I think there are two cases. The first is that there was more arp transmission before, but it was not visible because it was sent before link up. The second is that the phy link is unstable. It is recommended to check the phy twice by modifying as follows to ensure the stability of phy while (1) { check1 = getPHYCFGR () & PHYCFGR_LNK_ON check2 = getPHYCFGR () & PHYCFGR_LNK_ON if (check == 0x01 && check2 == 0x01) break; }

Caspar · Answer

The suggestion of polling the phy link twice worked. Thank you