W5500 chip + Arduino UNO on reference schematic can send/receive UDP messages, but TCP does not seem to work properly

Question

Hello, I’m a relatively new user to the W5500, so I apologize if I’m asking a simple question or overlooking something or if this post is not in the convention you prefer. However, here is my situation, hopefully someone can help: I used the reference schematic provided by Wiznet to craft my own iteration of the interface between an Arduino UNO over SPI to RJ-45/ethernet. I used this to base my own schematic off of. I can provide my own schematic as reference if this is in fact sounds like a hardware problem. I think the hardware might be OK however. The problem is this: Using the code below (note: this is written in “Arduino C”), I can talk using UDP to the server. Here’s a short dialog referencing that. So this implies to me that the hardware seems to work as intended. W5500Troubleshooting_11152×648 14.8 KB #include // needed for Arduino versions later than 0018 #include #include // UDP library from: bjoern@cs.stanford.edu 12/30/2008 // Enter a MAC address and IP address for your controller below. // The IP address will be dependent on your local network: byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x01 }; IPAddress ip(192, 168,0,200); unsigned int localPort = 8888; // local port to listen on // buffers for receiving and sending data char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet, char ReplyBuffer[] = "acknowledged"; // a string to send back // An EthernetUDP instance to let us send and receive packets over UDP EthernetUDP Udp; void setup() { // start the Ethernet and UDP: Ethernet.begin(mac,ip); Udp.begin(localPort); Serial.begin(9600); Serial.print("Server set up at: "); Serial.print(Ethernet.localIP()); Serial.println(); pinMode(2,OUTPUT); } void loop() { // if there's data available, read a packet int packetSize = Udp.parsePacket(); if(packetSize) { Serial.print("Received packet of size "); Serial.println(packetSize); Serial.print("From "); IPAddress remote = Udp.remoteIP(); for (int i =0; i < 4; i++) { Serial.print(remote[i], DEC); if (i < 3) { Serial.print("."); } } Serial.print(", port "); Serial.println(Udp.remotePort()); // read the packet into packetBufffer Udp.read(packetBuffer,UDP_TX_PACKET_MAX_SIZE); Serial.println("Contents:"); Serial.println(packetBuffer); for (int i=0; i<5; i++) { digitalWrite(2,HIGH); delay(500); digitalWrite(2,LOW); delay(500); } // send a reply, to the IP address and port that sent us the packet we received Udp.beginPacket(Udp.remoteIP(), Udp.remotePort()); Udp.write(ReplyBuffer); Udp.endPacket(); } delay(10); } However, when I attempt to use a very similar sketch over TCP, I can’t seem to communicate with the hardware. I can get connection between the two, but cannot send any data without the server (W5500 + Arduino) RST’ing the connection. Here is a wireshark dump of the responses using Hercules by HW-group.com to attempt to talk over a LAN using a HUB (not a SWITCH). So you can see that things are happening, the hardware thinks a client…

afarkas · Answer

I guess a more precise question would be: Is there anything in hardware or software that would cause a TCP connection to get RST from server side any time data is received from a client?

afarkas · Answer

Thank you Mxyxixptlick. Got the circuit to work. Turns out it WAS hardware related. Here is my OLD schematic: image1152×706 30.5 KB Turns out the inductor/bead that is circled there was “the” problem. Took it out and sure enough I can connect successfully via TCP without being instantly disconnected. Amazing to me that a simple inductor like that could cause such a problem. Seems like a potential timing or filtering problem if anyone is interested in troubleshooting the root cause.