memorybankad.java

这是一个以JAVA编写的程序,本人还没有试过,是一个简单的温度控制系统

      // loop to read the pages
      for (int pg = start_pg; pg <= end_pg; pg++)
         readPageCRC(pg, !(pg == start_pg), raw_buf,
                     (pg - start_pg) * PAGE_LENGTH);

      // extract out the data
      System.arraycopy(raw_buf, (startAddr % PAGE_LENGTH), readBuf, offset,
                       len);
   }

   /**
    * Write  memory in the current bank.  It is recommended that
    * when writing  data that some structure in the data is created
    * to provide error free reading back with read().  Or the
    * method 'writePagePacket()' could be used which automatically
    * wraps the data in a length and CRC.
    *
    * When using on Write-Once devices care must be taken to write into
    * into empty space.  If write() is used to write over an unlocked
    * page on a Write-Once device it will fail.  If write verification
    * is turned off with the method 'setWriteVerification(false)' then
    * the result will be an 'AND' of the existing data and the new data.
    *
    * @param  startAddr     starting address
    * @param  writeBuf      byte array containing data to write
    * @param  offset        offset into writeBuf to get data
    * @param  len           length in bytes to write
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void write (int startAddr, byte[] writeBuf, int offset, int len)
      throws OneWireIOException, OneWireException
   {
      byte[] raw_buf = new byte [7];
      int    cnt = 0, start_addr, addr, end_addr, lastcrc;

      // return if nothing to do
      if (len == 0)
         return;

      // attempt to put device at max desired speed
      checkSpeed();

      // select the device
      if (!ib.adapter.select(ib.address))
      {
         forceVerify();

         throw new OneWireIOException("Device select failed");
      }

      // build packet
      raw_buf [cnt++] = WRITE_MEMORY_COMMAND;
      start_addr      = startAddr + startPhysicalAddress;
      end_addr        = start_addr + len;
      raw_buf [cnt++] = ( byte ) (start_addr & 0xFF);
      raw_buf [cnt++] = ( byte ) (((start_addr & 0xFFFF) >>> 8) & 0xFF);

      // loop for each byte to write      
      for (addr = start_addr; addr < end_addr; addr++)
      {

         // add the byte to write to buffer
         raw_buf [cnt++] = writeBuf [offset + addr - start_addr];

         // initialize crc16
         lastcrc = CRC16.compute(raw_buf, 0, cnt, (addr == start_addr) ? 0
                                                                       : addr);

         // add the read crc and echo byte to block
         System.arraycopy(ffBlock, 0, raw_buf, cnt, 3);

         // perform the block
         ib.adapter.dataBlock(raw_buf, 0, cnt + 3);

         // check the CRC
         if (CRC16.compute(raw_buf, cnt, 2, lastcrc) != 0x0000B001)
         {
            forceVerify();

            throw new OneWireIOException("Invalid CRC16 read from device");
         }

         // check echo
         if (raw_buf [cnt + 2] != writeBuf [offset + addr - start_addr])
         {
            forceVerify();

            throw new OneWireIOException("Write byte echo was invalid");
         }

         // reset the buffer and loop
         cnt = 0;
      }
   }

   //--------
   //-------- PagedMemoryBank I/O methods
   //--------

   /**
    * Read  page in the current bank with no
    * CRC checking (device or data). The resulting data from this API
    * may or may not be what is on the 1-Wire device.  It is recommends
    * that the data contain some kind of checking (CRC) like in the
    * readPagePacket() method or have the 1-Wire device provide the
    * CRC as in readPageCRC().  readPageCRC() however is not
    * supported on all memory types, see 'hasPageAutoCRC()'.
    * If neither is an option then this method could be called more
    * then once to at least verify that the same thing is read consistantly.
    *
    * @param  page          page number to read packet from
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPage() continious where the last one
    *                       led off and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to place read data into
    * @param  offset        offset into readBuf to place data
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void readPage (int page, boolean readContinue, byte[] readBuf,
                         int offset)
      throws OneWireIOException, OneWireException
   {

      // read page with read page CRC
      readPageCRC(page, readContinue, readBuf, offset);
   }

   /**
    * Read  page with extra information in the current bank with no
    * CRC checking (device or data). The resulting data from this API
    * may or may not be what is on the 1-Wire device.  It is recommends
    * that the data contain some kind of checking (CRC) like in the
    * readPagePacket() method or have the 1-Wire device provide the
    * CRC as in readPageCRC().  readPageCRC() however is not
    * supported on all memory types, see 'hasPageAutoCRC()'.
    * If neither is an option then this method could be called more
    * then once to at least verify that the same thing is read consistantly.
    * See the method 'hasExtraInfo()' for a description of the optional
    * extra information some devices have.
    *
    * @param  page          page number to read packet from
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPage() continious where the last one
    *                       led off and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to place read data into
    * @param  offset        offset into readBuf to place data
    * @param  extraInfo     byte array to put extra info read into
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void readPage (int page, boolean readContinue, byte[] readBuf,
                         int offset, byte[] extraInfo)
      throws OneWireIOException, OneWireException
   {

      // only needs to be implemented if supported by hardware
      throw new OneWireException(
         "Read page with extra-info not supported by this memory bank");
   }

   /**
    * Read a Universal Data Packet.
    *
    * The Universal Data Packet always starts on page boundaries but
    * can end anywhere in the page.  The structure specifies the length of
    * data bytes not including the length byte and the CRC16 bytes.
    * There is one length byte. The CRC16 is first initialized to
    * the page number.  This provides a check to verify the page that
    * was intended is being read.  The CRC16 is then calculated over
    * the length and data bytes.  The CRC16 is then inverted and stored
    * low byte first followed by the high byte.  This is structure is
    * used by this method to verify the data but is not returned, only
    * the data payload is returned.
    *
    * @param  page          page number to read packet from
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPagePacket() continious where the last one
    *                       stopped and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to put data read. Must have at least
    *                       'getMaxPacketDataLength()' elements.
    * @param  offset        offset into readBuf to place data
    *
    * @return  number of data bytes read from the device and written to
    *          readBuf at the offset.
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public int readPagePacket (int page, boolean readContinue, byte[] readBuf,
                              int offset)
      throws OneWireIOException, OneWireException
   {
      byte[] raw_buf = new byte [PAGE_LENGTH];

      // read entire page with read page CRC
      readPageCRC(page, readContinue, raw_buf, 0);

      // check if length is realistic
      if (raw_buf [0] > (PAGE_LENGTH - 3))
         throw new OneWireIOException("Invalid length in packet");

      // verify the CRC is correct
      if (CRC16.compute(raw_buf, 0, raw_buf [0] + 3, page) == 0x0000B001)
      {

         // extract the data out of the packet
         System.arraycopy(raw_buf, 1, readBuf, offset, raw_buf [0]);

         // return the length
         return raw_buf [0];
      }
      else
      {
         forceVerify();

         throw new OneWireIOException("Invalid CRC16 in packet read");
      }
   }

   /**
    * Read a Universal Data Packet and extra information.  See the
    * method 'readPagePacket()' for a description of the packet structure.
    * See the method 'hasExtraInfo()' for a description of the optional
    * extra information some devices have.
    *
    * @param  page          page number to read packet from
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPagePacket() continious where the last one
    *                       stopped and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to put data read. Must have at least
    *                       'getMaxPacketDataLength()' elements.
    * @param  offset        offset into readBuf to place data
    * @param  extraInfo     byte array to put extra info read into
    *
    * @return  number of data bytes read from the device and written to
    *          readBuf at the offset.
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public int readPagePacket (int page, boolean readContinue, byte[] readBuf,
                              int offset, byte[] extraInfo)
      throws OneWireIOException, OneWireException
   {

      // only needs to be implemented if supported by hardware
      throw new OneWireException(
         "Read page packet with extra-info not supported by this memory bank");
   }

   /**
    * Write a Universal Data Packet.  See the method 'readPagePacket()'
    * for a description of the packet structure.
    *
    * @param  page          page number to write packet to
    * @param  writeBuf      data byte array to write
    * @param  offset        offset into writeBuf where data to write is
    * @param  len           number of bytes to write
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void writePagePacket (int page, byte[] writeBuf, int offset,
                                int len)
      throws OneWireIOException, OneWireException
   {

      // make sure length does not exceed max
      if (len > PAGE_LENGTH - 3)
         throw new OneWireIOException(
            "Length of packet requested exceeds page size");

      // construct the packet to write
      byte[] raw_buf = new byte [len + 3];

      raw_buf [0] = ( byte ) len;

      System.arraycopy(writeBuf, offset, raw_buf, 1, len);

      int crc = CRC16.compute(raw_buf, 0, len + 1, page);

      raw_buf [len + 1] = ( byte ) (~crc & 0xFF);
      raw_buf [len + 2] = ( byte ) (((~crc & 0xFFFF) >>> 8) & 0xFF);

      // write the packet, return result
      write(page * PAGE_LENGTH, raw_buf, 0, len + 3);
   }

   /**
    * Read a complete memory page with CRC verification provided by the
    * device.  Not supported by all devices.  See the method
    * 'hasPageAutoCRC()'.
    *
    * @param  page          page number to read
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPagePacket() continious where the last one
    *                       stopped and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to put data read. Must have at least
    *                       'getMaxPacketDataLength()' elements.
    * @param  offset        offset into readBuf to place data
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void readPageCRC (int page, boolean readContinue, byte[] readBuf,
                            int offset)
      throws OneWireIOException, OneWireException
   {
      byte[] raw_buf = new byte [5 + PAGE_LENGTH];
      int    len;

      // attempt to put device at max desired speed
      if (!readContinue)
         checkSpeed();

      // see if need to access the device
      if (!readContinue)
      {

         // select the device
         if (!ib.adapter.select(ib.address))
         {
            forceVerify();

            throw new OneWireIOException("Device select failed");
         }

         // build start reading memory block with: command, address
         len = raw_buf.length;

         System.arraycopy(ffBlock, 0, raw_buf, 0, len);

         raw_buf [0] = READ_MEMORY_COMMAND;

         int addr = page * PAGE_LENGTH + startPhysicalAddress;

         raw_buf [1] = ( byte ) (addr & 0xFF);
         raw_buf [2] = ( byte ) (((addr & 0xFFFF) >>> 8) & 0xFF);
      }
      else
      {
         len = PAGE_LENGTH + 2;

         System.arraycopy(ffBlock, 0, raw_buf, 0, len);
      }

      // do the block 
      ib.adapter.dataBlock(raw_buf, 0, len);

      // check the CRC
      if (CRC16.compute(raw_buf, 0, len, 0) != 0x0000B001)
      {
         forceVerify();

         throw new OneWireIOException("Invalid CRC16 read from device");
      }

      // extract the data to return
      System.arraycopy(raw_buf, len - 2 - PAGE_LENGTH, readBuf, offset,
                       PAGE_LENGTH);
   }

   /**
    * Read a complete memory page with CRC verification provided by the
    * device with extra information.  Not supported by all devices.
    * See the method 'hasPageAutoCRC()'.
    * See the method 'hasExtraInfo()' for a description of the optional
    * extra information.
    *
    * @param  page          page number to read
    * @param  readContinue  if 'true' then device read is continued without
    *                       re-selecting.  This can only be used if the new
    *                       readPagePacket() continious where the last one
    *                       stopped and it is inside a
    *                       'beginExclusive/endExclusive' block.
    * @param  readBuf       byte array to put data read. Must have at least
    *                       'getMaxPacketDataLength()' elements.
    * @param  offset        offset into readBuf to place data
    * @param  extraInfo     byte array to put extra info read into
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void readPageCRC (int page, boolean readContinue, byte[] readBuf,
                            int offset, byte[] extraInfo)
      throws OneWireIOException, OneWireException
   {

      // only needs to be implemented if supported by hardware
      throw new OneWireException(
         "Read page with CRC and extra-info not supported by this memory bank");
   }

   //--------
   //-------- checkSpeed methods
   //--------

   /**
    * Check the device speed if has not been done before or if
    * an error was detected.
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void checkSpeed ()
      throws OneWireIOException, OneWireException
   {
      synchronized (this)
      {

         // only check the speed 
         if (doSetSpeed)
         {

            // attempt to set the correct speed and verify device present
            ib.doSpeed();

            // no execptions so clear flag 
            doSetSpeed = false;
         }
      }
   }

   /**
    * Set the flag to indicate the next 'checkSpeed()' will force
    * a speed set and verify 'doSpeed()'.
    */
   public void forceVerify ()
   {
      synchronized (this)
      {
         doSetSpeed = true;
      }
   }
}