Can not wake up PICC

[omersiar]

This simple code tries to Wake UP a Halted PICC, but it can not. What is wrong?

include <SPI.h> // RC522 Module uses SPI protocol

include <MFRC522.h> // Library for Mifare RC522 D

define SS_PIN 10

define RST_PIN 9

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.

void setup() {
// put your setup code here, to run once:
Serial.begin(9600); // Initialize serial communications with PC
SPI.begin(); // MFRC522 Hardware uses SPI protocol
mfrc522.PCD_Init(); // Initialize MFRC522 Hardware

}

void loop() {
byte bufferATQA[10];
byte bufferSize[10];
// put your main code here, to run repeatedly:
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent()) {
Serial.println("There is no PICC");
return;
}

// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial()) {
Serial.println("Cannot get UID");
return;
}
Serial.println("GOT UID");
mfrc522.PICC_HaltA();
Serial.println("PICC Halted");
delay(100);
Serial.println("Im trying to Wake Up Halted PICC");
mfrc522.PICC_WakeupA(bufferATQA, bufferSize); //wake up PICC which was previously Halted
delay(100);
mfrc522.PICC_RequestA(bufferATQA, bufferSize);
delay(100);
Serial.println("PICC Should Wake Up");
delay(100);
if ( ! mfrc522.PICC_ReadCardSerial()) {
Serial.println("Tried get UID but no luck");
}
delay(1000);
}

[mdxs]

Look at the implementation of MFRC522::PICC_IsNewCardPresent() in the .cpp, from that I guess you will need to use:

  byte bufferATQA[10];
  byte bufferSize = sizeof(bufferATQA);
  byte result;
  ...
  result = mfrc522.PICC_WakeupA(bufferATQA, &bufferSize);
  if (result != STATUS_OK) {
    // report some issue
    return;
  }
  ...
  result = mfrc522.PICC_RequestA(bufferATQA, &bufferSize);
  if (result != STATUS_OK) {
    // report some issue
    return;
  }
  ...

[mdxs]

@omersiar : could this issue be closed now?

[omersiar]

Yes it can be closed.

[Lotrax]

I have the same problem as @omersiar and have looked at the .cpp but it seems I'm missing something. Currently doing it as follows:

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

#define RST_PIN         13          // Configurable, see typical pin layout above
#define SS_1_PIN        2         // Configurable, take a unused pin, only HIGH/LOW required, must be diffrent to SS 2
#define SS_2_PIN        3          // Configurable, take a unused pin, only HIGH/LOW required, must be diffrent to SS 1
#define SS_3_PIN        4
#define SS_4_PIN        5
#define SS_5_PIN        6
#define SS_6_PIN        7

#define NR_OF_READERS   6

byte ssPins[] = {SS_1_PIN, SS_2_PIN, SS_3_PIN, SS_4_PIN, SS_5_PIN, SS_6_PIN};

byte bufferATQA[2];
byte bufferSize = sizeof(bufferATQA);

MFRC522 mfrc522[NR_OF_READERS];   // Create MFRC522 instance.

void setup() {
  Serial.begin(9600); // Initialize serial communications with the PC
  SPI.begin();        // Init SPI bus
  delay(500);

  for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {
    mfrc522[reader].PCD_Init(ssPins[reader], RST_PIN); // Init each MFRC522 card
    delay(100);
    Serial.print(F("Reader "));
    Serial.print(reader);
    Serial.print(F(": "));
    mfrc522[reader].PCD_DumpVersionToSerial();
  }
}

/**
   Main loop.
*/
void loop() {

  for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {
    mfrc522[reader].PICC_WakeupA(bufferATQA, bufferSize);

    if (mfrc522[reader].PICC_IsNewCardPresent() && mfrc522[reader].PICC_ReadCardSerial()) {
      Serial.print(F("Reader "));
      Serial.print(reader);
      dump_byte_array(mfrc522[reader].uid.uidByte, mfrc522[reader].uid.size);
      Serial.println();

      mfrc522[reader].PICC_HaltA(); //Remove so cards stay readable
      mfrc522[reader].PCD_StopCrypto1();
    }
  }
}

void dump_byte_array(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }

I know I can just leave out mfrc522[reader].PICC_HaltA(); but I want more control over it, I want to keep reading all readers except those I have halted. I want to start those readers that are relevant.

[Lotrax]

Another user, @akellai, has created a fast_reset function, which does exactly what I wanted PICC_WakeupA to do (or expected it to do). It's perhaps a work around, but it works. Since Google led me to this question, I suspect others will find it to, so here is a link to akellai's comment and my own which is an adapted code of akellia's for multiple readers.