RDM880 RFID reading anomaly on Arduino

Question

I've an RDM880 HW to read some 13.56MHz cards.

I've read the protocol of comunication and writed a sketch following some guides i found on the net. I'm able print on serial the response from the reciver correctly, but when i try to store it to use it, i encountering some problems. Following My code:

byte MF_GET_SNR[8] = {0xAA, 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB};


void setup() {


  Serial.begin(9600);
  Serial1.begin(9600);

}

void loop() {
  Serial1.write(MF_GET_SNR, 8);
   delay(1000);

   while(Serial1.available() > 0) {
    Serial.print(Serial1.read(), HEX);
    Serial.print(" ");  
   }
   Serial.println(); 
}

I get this on serial monitor:

AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 6 0 0 ED B F0 6C 7C BB 
AA 0 6 0 0 ED B F0 6C 7C BB 
AA 0 6 0 0 ED B F0 6C 7C BB 
AA 0 6 0 0 ED B F0 6C 7C BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB 
AA 0 2 1 83 80 BB

Where AA 0 6 0 0 ED B F0 6C 7C BB is the answare of the reciver when i put the card, where this ED B F0 6C should be the RFID of the card and

When i alter my code to store and use the data i get from the reciver in this way my problem starts:

byte MF_GET_SNR[8] = {0xAA, 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB};

void setup() {


  Serial.begin(9600);
  Serial1.begin(9600);

}

void loop() {
  Serial1.write(MF_GET_SNR, 8);
   delay(1000);

   char rfid[1024];
  for (int i=0;i<14;i++) rfid[i]='0';
  int counter=0;
  while (Serial1.available()){
    //var=Serial1.read();

    rfid[counter]=Serial1.read();
    actived=true;
    Serial.print("Recived Element: "); Serial.println(rfid[counter],HEX);
    counter++;
    //Serial.println("CHECK1");
    if (counter > 14) break;
  }
}

And this the data i get:

Recived Element: FFFFFFAA
Recived Element: 0
Recived Element: 2
Recived Element: 1
Recived Element: FFFFFF83
Recived Element: FFFFFF80
Recived Element: FFFFFFBB

Recived Element: FFFFFFAA
Recived Element: 0
Recived Element: 6
Recived Element: 0
Recived Element: 0
Recived Element: 2B
Recived Element: FFFFFFA8
Recived Element: FFFFFFB5
Recived Element: FFFFFF9E
Recived Element: FFFFFFAE
Recived Element: FFFFFFBB

I cant understand how fix the problem with the FFFFFF readed in front of the HEX values.

Doesent seems to be a problem of baudrate becouse if i only try to read the data i get the correct values.

What i'm tryng to achive have to get this at the end: var="AA00060000ED0BF06C7CBB"

score 0 · Answer 1 · answered Mar 06 '15 at 12:02

0

The problem can be solved setting as "unsigned char rfid[1024]". I didnt have this problem with other RFID reader but seems to be needed for this model.

answered Mar 06 '15 at 12:02

groot

57
1
9

score 0 · Accepted Answer · answered Mar 06 '15 at 17:17

byte MF_GET_SNR[8] = {0xAA, 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB};
/* This will contain the RFID receiver response 
   (11 is taken from your example) */
byte RFID_DATA[11]; 
int RFID_DATA_index;

void setup() {
    Serial.begin(9600);
    Serial1.begin(9600);
}

void loop() {
    Serial1.write(MF_GET_SNR, 8);
    delay(1000);
    RFID_DATA_index = 0;
    while(Serial1.available() > 0) {
        /* Store RFID received response data */
        RFID_DATA[RFID_DATA_index] = Serial1.read();
        /* This will print the card RFID */
        if(RFID_DATA_index > 4){
            Serial.print(RFID_DATA[RFID_DATA_index], HEX)
        }
        RFID_DATA_index++;
    }
    Serial.print('\n'); 
}

RDM880 RFID reading anomaly on Arduino

2 Answers2