Interfacing ESP-WROOM-32 with WIZnet W5500

Question

Hi everyone, I’m building a network-enabled sensor using an ESP-WROOM-32 Module Development Board. I’m trying to add wired Ethernet support via a WIZnet W5500 Ethernet module, but I’m running into trouble getting the network interface to work reliably. So far, I've connected ESP32 and W5500 via SPI using standard pins (SCLK, MISO, MOSI, CS) Used the Wiznet example code with Ethernet.init(CSN);, Ethernet.begin(mac, ip); and tested via EthernetClient APIs. Occasionally, the module gets a proper IP and pings out, but most times the Ethernet.begin() call fails or returns a DHCP timeout. Things I’ve checked: SPI frequency: dropped from 10 MHz to 4 MHz; marginal improvements but still very unreliable. Double checked wiring and logic levels, both 3.3 V, no issues found. Tried both DHCP and static IP setups, same inconsistent behavior. Are there recommended BIOS/configuration pins or initialization sequences required? Any issue with the ESP32 toggling from Wi-Fi to Ethernet mode, could it be causing intermittent SPI lockups? Would love to hear about what’s worked for you, especially practical tips on wiring or init code to get the ESP32 + WIZnet combo running solidly. Thanks in advance!

Lihan__ · Answer

Please first check that the physical wiring between the ESP32 and W5500 is correct. Since PING responses were successful, the pin configuration itself seems fine. However, we ask you to verify the SPI waveform with an oscilloscope and check if any noise is present. In addition, please capture the actual packet flow using Wireshark to confirm that packets are being transmitted correctly.