I'm responsible for Ethernet so I usually seek for Ethernet related topics here on forum. Therefore I simply missed it since it's been related to forum functionality... Approved now.

Hi Michael, the trick is the ESP32-C6 does not have internal EMAC with MII/RMII. Therefore it's not shown in the selector. However, you can connect SPI Ethernet module to it. That's the reason why Ethernet examples support even these targets without internal EMAC. The only chips with internal EMAC a...

That's strange, "insufficient buffer size error" should not occur in "basic" example! Could you please provide more information about your setup?
- What board do you use?
- What is your exact IDF version?
- Please share logs from "basic" example if insufficient buffer size error occurs.

What example do you run? Anyway, it indicates you are trying to transmit more data than the hardware is able to process, i.e. you are reaching to limit of maximum Ethernet bandwidth of 100 Mbps. In reality it little bit less. You need to limit bandwidth. With default configuration of 10 Tx buffers, ...

Hi FrankJensen, could you please double check that you initialized the Ethernet driver correctly? The thing is that basically exactly the same interrupt initialization as yours is performed by the driver: esp_rom_gpio_pad_select_gpio(emac->int_gpio_num); gpio_set_direction(emac->int_gpio_num, GPIO_M...

Here is a code example to dump PHY registers: esp_err_t dump_phy_regs(esp_eth_handle_t *eth_handle, uint32_t start_addr, uint32_t end_addr) { esp_eth_phy_reg_rw_data_t reg; uint32_t reg_val; reg.reg_value_p = ®_val; printf("--- PHY Registers Dump ---\n"); for (uint32_t curr_addr = start_addr; cur...

Create an app to transmit same data in a loop and measure the RMII Tx signal path on your board. You need to see the signal at the ESP32 output and the same at PHY input.

Ethernet driver always initializes the Rx task from which is the callback called. Therefore, you don't save any resources if you use `mac->receive` function directly. Just use the callback. If you don't need the Ethernet after receiving your frame, you can stop it and de-initialize it.

Why you don't want to use callback? Using `mac->receive` is not designed to be called from user code.

It seems your board is able to receive frames so the Rx path works. Now, check if Tx path works too. Connect your board to a PC and capture traffic using e.g. Wireshark to see if your board sends DHCP request. You can also try to run loopback test to see if there is no issue with RMII (https://githu...