Users frequently source these custom library files ( .idx , .lib ) from electronics hobbyist forums, such as The Engineering Projects .
: Write your control logic in an IDE (like the Arduino IDE). Compile the code to generate a .hex file.
MFRC522 mfrc522(SS_PIN, RST_PIN);
Type or "MFRC522" in the keywords box. Select the module from the results to add it to your project. 4. Interfacing and Pinout
Do not confuse the RC522.HEX simulation model with the Arduino firmware HEX file. The library model emulates the RC522 chip itself; the Arduino HEX runs your custom sketch.
