I double checked and I was kind of wrong. SMI is non standard version of MII so it was not implemented due to lack of time. You can access all registers via SMI. Try the following: * remove `ksz8863_ctrl_intf_init` from `ksz8863_board_specific_init` so the I2C/SPI is not going to be initialized * up...

If I remember correctly, it is not possible to access all registers via SMI => you can manage only host port and you cannot mange the other ports or switch configuration. That was the reason why SMI is not implemented because it didn't worth. Please consult with switch chip documentation for more in...

Could you please clarify what do you mean by W5500 EMAC mode?

This issue happens when your application consumes a lot of memory and if Ethernet messages are received with short interval. The size of packet doesn't matter since the driver always allocates 1500B. The driver was optimized in ESP-IDF v5.0 and above. I recently backported the optimization to v4.3 a...

Just note that performance may vary. It is affected by your application code, cache misses, etc. Difference between KSZ8851 and W5500 is not that significant. Therefore, if I were you, I would also consider other factors (price, availability, etc.).

See below for same performance comparison (for ESP32). +---------------------+---------+------------+---------+ | Proto / direction | EMAC | KSZ8851* | W5500* | +---------------------+---------+------------+---------+ | TCP Rx [Mbps] | 31 | 13 | 10 | | TCP Tx [Mbps] | 59 | 15 | 14 | | UDP Rx [Mbps] ...

What ESP-IDF version do you use?

Do other devices on your local network get assigned IP addresses from DHCP server? It's strange since your device receives Ethernet frames as indicated by the log you provided. If I were you, I would connect the device directly to a PC with DHCP server running and capture traffic to see what's going...

Could you please try to set EMAC DMA burst length to e.g. EMAC_LL_DMA_BURST_LENGTH_4BEAT at https://github.com/espressif/esp-idf/bl ... hal.c#L301?

Note that there is user configuration option for this in higher IDF versions.

Read documentation at https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/network/esp_eth.html#configure-mac-and-phy and get familiar with REF RMII CLK options. In case of LAN8720, I recommend to use GPIO17 as CLK source to avoid board reset and startup issues, see https://www....