代码:我正在使用MFRC522 1.4.5库和一个Arduino Uno以及一个RFID RC522。 我试图有一个LED灯，每当我扫描RFID模块与卡或钥匙。

另一个注意事项是，我对Arduino中的编码并不是太熟悉，我主要是想学习电路（然而，我确实了解编码概念，因为我有Python和Java的背景，我只是不知道应该如何解释这些错误消息）。

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

    #define SDAPIN 10
    #define RESETPIN 8
    #define LED 4

    byte FoundTag; // Variable used to check if Tag was found
    byte ReadTag; // Variable used to store anti-collision value to read Tag information
    byte TagData[MAX_LEN]; // Variable used to store Full Tag Data
    byte TagSerialNumber[5]; // Variable used to store only Tag Serial Number
    byte GoodTagSerialNumber[5] = {0x22, 0x23, 0x15, 0xD}; // The Tag Serial number we are looking for

    MFRC522 nfc(SDAPIN, RESETPIN);

    void setup() {
        SPI.begin(); // Opens up the communicationto the serial monitor in Arduino IDE
        Serial.begin(9600); 
        pinMode(LED, OUTPUT); // Setup the pin 4 to be the output of LED
        // Start to find an RFID Module
        Serial.println("Looking for RFID Reader");
        nfc.begin();
        byte version = nfc.getFirmwareVersion(); // Variable to store Firmware version of the Module
        // If can't find an RFID Module
        if (! version) {
            Serial.print("Didn't find RC522 board.");
            while (1); //Wait until a RFID Module is found
        }
        // If found, print the information about the RFID Module
        Serial.print("Found chip RC522 ");
        Serial.print("Firmware version: 0x");
        Serial.println(version, HEX);
        Serial.println();
    }

    void loop() {
        String GoodTag = "False"; // Variable used to confirm good Tag Detected
        // Check to see if a Tag was detected
        // If yes, then the variable FoundTag will contain "MI_OK"
        FoundTag = nfc.requestTag(MF1_REQIDL, TagData);
        if (FoundTag == MI_OK) {
        delay(200);
            // Get anti-collision value to properly read information from the Tag
            ReadTag = nfc.antiCollision(TagData);
            memcpy(TagSerialNumber, TagData, 4); // the tag information in the TagSerialNumber variable
            // Check if detected Tag has the right Serial number we are looking for
            for (int i = 0; i < 4; i++) {
                if (GoodTagSerialNumber[i] != TagSerialNumber[i]) {
                break; // if not equal, then break out of the "for" loop
                }
                if (i == 3) { // if we made it to 4 loops then the Tag Serial numbers are matching
                    GoodTag = "TRUE";
                }
            }   
            if (GoodTag == "TRUE") {
                Serial.println("Success!");
                Serial.println();
                digitalWrite(LED, HIGH);
                delay(1500);
            }
            else {
                Serial.println("TAG NOT ACCEPTED");
                Serial.println();
                digitalWrite(LED, LOW);
            }
            delay(500);
        }    
  
    }    

以下是我收到的错误消息:

Arduino: 1.8.12 (Windows 10), Board: "Arduino Uno"

RFID-RC522_LED:10:14: error: 'MAX_LEN' was not declared in this scope

 byte TagData[MAX_LEN]; // Variable used to store Full Tag Data

              ^~~~~~~

C:\Users\jeffo\Arduino\Code\RFID-RC522_LED\RFID-RC522_LED.ino: In function 'void setup()':

RFID-RC522_LED:22:7: error: 'class MFRC522' has no member named 'begin'

   nfc.begin();

       ^~~~~

RFID-RC522_LED:23:22: error: 'class MFRC522' has no member named 'getFirmwareVersion'

   byte version = nfc.getFirmwareVersion(); // Variable to store Firmware version of the Module

                      ^~~~~~~~~~~~~~~~~~

C:\Users\jeffo\Arduino\Code\RFID-RC522_LED\RFID-RC522_LED.ino: In function 'void loop()':

RFID-RC522_LED:40:18: error: 'class MFRC522' has no member named 'requestTag'

   FoundTag = nfc.requestTag(MF1_REQIDL, TagData);

                  ^~~~~~~~~~

RFID-RC522_LED:40:29: error: 'MF1_REQIDL' was not declared in this scope

   FoundTag = nfc.requestTag(MF1_REQIDL, TagData);

                             ^~~~~~~~~~

RFID-RC522_LED:40:41: error: 'TagData' was not declared in this scope

   FoundTag = nfc.requestTag(MF1_REQIDL, TagData);

                                         ^~~~~~~

RFID-RC522_LED:41:19: error: 'MI_OK' was not declared in this scope

   if (FoundTag == MI_OK) {

                   ^~~~~

C:\Users\jeffo\Arduino\Code\RFID-RC522_LED\RFID-RC522_LED.ino:41:19: note: suggested alternative: 'MISO'

   if (FoundTag == MI_OK) {

                   ^~~~~

                   MISO

RFID-RC522_LED:44:19: error: 'class MFRC522' has no member named 'antiCollision'

     ReadTag = nfc.antiCollision(TagData);

                   ^~~~~~~~~~~~~

exit status 1
'MAX_LEN' was not declared in this scope

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