Are GPIOs labelled EMAC used by the PoE Ethernet?

[iPeel]

Hi,

I'm trying to find a pin on the ESP32-PoE that's not automatically pulled up, and the only options seemingly are the battery sensor and some of the pins that are listed on the pinout diagram as being used by "EMAC".

Are the GPIOs that are labelled EMAC_ ( GPIOs 0, 1, 4, 5, 16, 32, 33 ) used at all by the inbuilt Ethernet controller or are they free to use even if using the ESP32-PoE's Ethernet?


Thanks,


Neil.

[LubOlimex]

Pins used for the Ethernet are not free.

For free pins first check the UEXT connector. Then check what is available on the EXT headers. Then if you need more and if you don't have SD card inserted, you can use the pins for SD/MMC.

[iPeel]

Thanks,

On the UEXT GPIOs 4, 5 and 16 are labelled EMAC and I assume used by Ethernet.

The rest seem to be pulled high when used as an input, even when registering the pinMode as INPUT and not INPUT_PULLUP.

The only non-EMAC pin that is not like this is GPIO35 which is shared with the battery voltage sensor.


Neil.

[LubOlimex]

GPIO4, GPIO5, and GPIO16 are not used for the Ethernet.

The ESP32 module has huge multiplexing. If you look at GPIO4 - the pin has 8 different options for operation. If you wish to confirm that they are not used for the Ethernet, better inspect the Ethernet part of the schematic and confirm that the pins are not used there.

GPIO35 is not GPIO, it is only GPI35. It can't be output (due to ESP32 module design). And by default it should be free to use, battery measuring is not enabled by default. It will be connected to the battery measuring voltage divider if you close (solder its pads together) jumper BAT_SENS_E1.

[iPeel]

OK thanks. That was the nature of my original question, that when you look at the pinout on the ESP32-PoE page it mentions some GPIOs reserved by EMAC, and these are GPIOs 0, 1, 4, 5, 16, 32, 33. I wondered if these were useable when the Ethernet port of the ESP32-POE is used.

If there are no requirements for these and only the GPIOs on the schematic I will check those.