Getting error in the MFRC522.h library while connecting ESP 32 with RFID reader

Projects Programming
1

The code is working with Arduino uno but not with esp32Here i am attaching error and the code.

Error:
c:\Users\steph\OneDrive\Documents\Arduino\libraries\MFRC522\src\MFRC522Extended.cpp: In member function 'MFRC522::StatusCode MFRC522Extended::TCL_Transceive(TagInfo*, byte*, byte, byte*, byte*)':
c:\Users\steph\OneDrive\Documents\Arduino\libraries\MFRC522\src\MFRC522Extended.cpp:824:34: error: ordered comparison of pointer with integer zero ('byte*' {aka 'unsigned char*'} and 'int')
824 | if (backData && (backLen > 0)) {
| ~~~~~~^
c:\Users\steph\OneDrive\Documents\Arduino\libraries\MFRC522\src\MFRC522Extended.cpp:847:42: error: ordered comparison of pointer with integer zero ('byte*' {aka 'unsigned char*'} and 'int')
847 | if (backData && (backLen > 0)) {
| ~~~~~~^

exit status 1

Compilation error: exit status 1

code:

/*

#include <SPI.h>
#include <MFRC522.h>

#define SS_PIN 5
#define RST_PIN 27

MFRC522 rfid(SS_PIN, RST_PIN);

void setup() {
Serial.begin(115200);
SPI.begin(); // init SPI bus
rfid.PCD_Init(); // init MFRC522

Serial.println("Tap RFID/NFC Tag on reader");
}

void loop() {
if (rfid.PICC_IsNewCardPresent()) { // new tag is available
if (rfid.PICC_ReadCardSerial()) { // NUID has been readed
MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
//Serial.print("RFID/NFC Tag Type: ");
//Serial.println(rfid.PICC_GetTypeName(piccType));

  // print NUID in Serial Monitor in the hex format
  Serial.print("UID:");
  for (int i = 0; i < rfid.uid.size; i++) {
    Serial.print(rfid.uid.uidByte[i] < 0x10 ? " 0" : " ");
    Serial.print(rfid.uid.uidByte[i], HEX);
  }
  Serial.println();

  rfid.PICC_HaltA(); // halt PICC
  rfid.PCD_StopCrypto1(); // stop encryption on PCD
}

}
}

2

I moved your topic to an appropriate forum category @stephen_a.

In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.

This is an important part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. The guide contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

3

with the ESP32 I used the Arduino_MFRC522v2 library which worked OK

4

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