RC522 Wiring

[hummel13]

Hi,

I'm having trouble connecting an RC522 rfid reader to my esp32 module. I have the esp32-Lora module from Heltec with the built-in Oled and lora functionality.

Here is the pin diagram for this module:

Heltec_WIFI-LoRa-32_DiagramPinoutFromTop.jpg (117.4 KiB) Viewed 6606 times

And here is the diagram for the Rc522

NFC-RC522-Module-for-Arduino.png (230.95 KiB) Viewed 6606 times

However, I don't understand how I should wire the reader to the module as it is written in the diagram "Pins with an arrow are used by on-board lora or Oled. They must not be used for other purposes unless you know what you are doing!".

I tried a lot of different wiring, but could not get it to work.

Any help would be greatly appreciated!
Thanks

[martinayotte]

Since this modules can either work using SPI or I2C, why simply use the I2C bus shared with OLED ?
Simply attached the SDA/SCL pins.

[BlackSeal7]

I Have tried to connect to I2C bus on Wemos Lolin32 Oled Board that is pin no. 5, 4 (SDA/SCL) which is also shared with Oled as 5 and 4 is dedicated I2C pins on this board. But while I run the code It says MFRC22 in not connected properly.


I have also tried to connect the mfrc522 through SPI bus using pins as MOSI=13, MISO=12, SCK=14, SS=2, RST=0, it is working alone but not working while add Wifi library to it. Please Help me if It is possible in some other ways..!!