how to connect RFID reader +ESP32 Gateway board functional SD card,Ethernet

[laserman]

Hi
I want to use RFID Reader/writer MFRC522 board with ESP32 Gateway board
same time functional MicroSD card, Ethernet 100Mb interface in use.

in this configuration   As per Pin layout very limited Pin are available.

please guide me how to re assign ESP32 pins for    SDA MISO MOSI RST SCK  to connect RFID board.
standard communication PIN engaged with Micro SD & Ethernet.

thanks
Regards
 
 

[LubOlimex]

GPIO16, GPIO32, GPI35, GPI36, GPI39 are free (notice that 35, 36, 39 can only be inputs regarding the ESP32 module).

If you need more and you don't need user button or user LED You can also free GPIO33 and GPI34. To free GPIO33 remove the LED1, to free GPI34 remove R45.

Refer to the schematic export for more info.

[KeviNH]

I've been trying a few different options to read NFC (via RC522) with ESP32-POE.  Eventually figured out that to keep the RC522 stable, must add a 47uF electrolytic cap across Vcc+Gnd.

Regarding pin count, I eventually settled on HSU polling, needs just two GPIOs (Serial1 TX & RX).