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PN532_I2C/PN532_I2C.cpp 4.25 KB
1a2e5ee4   henyxia   Big revision
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  #include "PN532_I2C.h"
  #include "PN532_debug.h"
  #include "Arduino.h"
  
  #define PN532_I2C_ADDRESS       (0x48 >> 1)
  
  
  PN532_I2C::PN532_I2C(TwoWire &wire)
  {
      _wire = &wire;
      command = 0;
  }
  
  void PN532_I2C::begin()
  {
      _wire->begin();
  }
  
  void PN532_I2C::wakeup()
  {
      _wire->beginTransmission(PN532_I2C_ADDRESS); // I2C start
      delay(20);
      _wire->endTransmission();                    // I2C end
  }
  
  int8_t PN532_I2C::writeCommand(const uint8_t *header, uint8_t hlen, const uint8_t *body, uint8_t blen)
  {
      command = header[0];
      _wire->beginTransmission(PN532_I2C_ADDRESS);
      
      write(PN532_PREAMBLE);
      write(PN532_STARTCODE1);
      write(PN532_STARTCODE2);
      
      uint8_t length = hlen + blen + 1;   // length of data field: TFI + DATA
      write(length);
      write(~length + 1);                 // checksum of length
      
      write(PN532_HOSTTOPN532);
      uint8_t sum = PN532_HOSTTOPN532;    // sum of TFI + DATA
      
      DMSG("write: ");
         
      for (uint8_t i = 0; i < hlen; i++) {
          if (write(header[i])) {
              sum += header[i];
              
              DMSG_HEX(header[i]);
          } else {
              DMSG("\nToo many data to send, I2C doesn't support such a big packet\n");     // I2C max packet: 32 bytes
              return PN532_INVALID_FRAME;
          }
      }
  
      for (uint8_t i = 0; i < blen; i++) {
          if (write(body[i])) {
              sum += body[i];
              
              DMSG_HEX(body[i]);
          } else {
              DMSG("\nToo many data to send, I2C doesn't support such a big packet\n");     // I2C max packet: 32 bytes
              return PN532_INVALID_FRAME;
          }
      }
    
      uint8_t checksum = ~sum + 1;            // checksum of TFI + DATA
      write(checksum);
      write(PN532_POSTAMBLE);
      
      _wire->endTransmission();
      
      DMSG('\n');
  
      return readAckFrame();
  }
  
  int16_t PN532_I2C::readResponse(uint8_t buf[], uint8_t len, uint16_t timeout)
  {
      uint16_t time = 0;
  
      do {
          if (_wire->requestFrom(PN532_I2C_ADDRESS, len + 2)) {
              if (read() & 1) {  // check first byte --- status
                  break;         // PN532 is ready
              }
          }
  
          delay(1);
          time++;
          if ((0 != timeout) && (time > timeout)) {
              return -1;
          }
      } while (1); 
      
      if (0x00 != read()      ||       // PREAMBLE
              0x00 != read()  ||       // STARTCODE1
              0xFF != read()           // STARTCODE2
          ) {
          
          return PN532_INVALID_FRAME;
      }
      
      uint8_t length = read();
      if (0 != (uint8_t)(length + read())) {   // checksum of length
          return PN532_INVALID_FRAME;
      }
      
      uint8_t cmd = command + 1;               // response command
      if (PN532_PN532TOHOST != read() || (cmd) != read()) {
          return PN532_INVALID_FRAME;
      }
      
      length -= 2;
      if (length > len) {
          return PN532_NO_SPACE;  // not enough space
      }
      
      DMSG("read:  ");
      DMSG_HEX(cmd);
      
      uint8_t sum = PN532_PN532TOHOST + cmd;
      for (uint8_t i = 0; i < length; i++) {
          buf[i] = read();
          sum += buf[i];
          
          DMSG_HEX(buf[i]);
      }
      DMSG('\n');
      
      uint8_t checksum = read();
      if (0 != (uint8_t)(sum + checksum)) {
          DMSG("checksum is not ok\n");
          return PN532_INVALID_FRAME;
      }
      read();         // POSTAMBLE
      
      return length;
  }
  
  int8_t PN532_I2C::readAckFrame()
  {
      const uint8_t PN532_ACK[] = {0, 0, 0xFF, 0, 0xFF, 0};
      uint8_t ackBuf[sizeof(PN532_ACK)];
      
      DMSG("wait for ack at : ");
      DMSG(millis());
      DMSG('\n');
      
      uint16_t time = 0;
      do {
          if (_wire->requestFrom(PN532_I2C_ADDRESS,  sizeof(PN532_ACK) + 1)) {
              if (read() & 1) {  // check first byte --- status
                  break;         // PN532 is ready
              }
          }
  
          delay(1);
          time++;
          if (time > PN532_ACK_WAIT_TIME) {
              DMSG("Time out when waiting for ACK\n");
              return PN532_TIMEOUT;
          }
      } while (1); 
      
      DMSG("ready at : ");
      DMSG(millis());
      DMSG('\n');
      
  
      for (uint8_t i = 0; i < sizeof(PN532_ACK); i++) {
          ackBuf[i] = read();
      }
      
      if (memcmp(ackBuf, PN532_ACK, sizeof(PN532_ACK))) {
          DMSG("Invalid ACK\n");
          return PN532_INVALID_ACK;
      }
      
      return 0;
  }