rfid.cpp

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

#include "global.h"
#include "log.h"
#include "rfid.h"
#include "display.h"

SPIClass RFID_SPI(HSPI);
MFRC522_SPI spiDevice = MFRC522_SPI(RFID_CS, RFID_RESET, &RFID_SPI);
MFRC522 mfrc522 = MFRC522(&spiDevice);

// Very ugly global vars - used to communicate between the REST call and the rest.
//
char tag[128] = { 0 };

unsigned int rfid_scans = 0, rfid_miss = 0;
bool setupRFID()
{
  RFID_SPI.begin(RFID_SCLK, RFID_MISO, RFID_MOSI, RFID_CS);
  mfrc522.PCD_Init();

  // Lookup which version - coppied from PubSub
  //
  byte v = mfrc522.PCD_ReadRegister(mfrc522.VersionReg);

  // When 0x00 or 0xFF is returned, communication probably failed
  if ((v == 0x00) || (v == 0xFF)) {
    Log.println(F("RFID scanner Communication failure, is the MFRC522 properly wired up?"));
    return false;
  };

  Log.print(F("MFRC522 (rfid reader/writer) Firmware Version: 0x"));
  Log.print(v, HEX);
  switch (v) {
    case 0x88: Log.println(F(" = (clone)"));  break;
    case 0x90: Log.println(F(" = v0.0"));     break;
    case 0x91: Log.println(F(" = v1.0"));     break;
    case 0x92: Log.println(F(" = v2.0"));     break;
    case 0x12: Log.println(F(" = counterfeit chip"));     break;
    default:   Log.println(F(" = (unknown - may be wired wrong/broken)"));
  }
  return true;
}

bool loopRFID() {
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return false;
  }

  if ( ! mfrc522.PICC_ReadCardSerial()) {
    Log.println("Bad read (was card removed too quickly ? )");
    rfid_miss++;
    return false;
  }
  if (mfrc522.uid.size == 0) {
    Log.println("Bad card (size = 0)");
    rfid_miss++;
    return false;
  };

  // We're somewhat strict on the parsing/what we accept; as we use it unadultared in the URL.
  if (mfrc522.uid.size > sizeof(mfrc522.uid.uidByte)) {
    Log.println("Too large a card id size. Ignoring.)");
    rfid_miss++;
    return false;
  };

  memset(tag, 0, sizeof(tag));
  for (int i = 0; i < mfrc522.uid.size; i++) {
    char buff[5]; // 3 digits, dash and \0.
    snprintf(buff, sizeof(buff), "%s%d", i ? "-" : "", mfrc522.uid.uidByte[i]);
    strncat(tag, buff, sizeof(tag) - 1);
  };

  Log.println("Good scan");
  rfid_scans++;
  mfrc522.PICC_HaltA();
  return true;
}