memorybankscratch.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

      // 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
   {
      byte[] raw_buf = new byte [pageLength];

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

      // read the scratchpad, discard extra information
      readScratchpad(raw_buf, 0, pageLength, extraInfo);

      // check if length is realistic
      if (raw_buf [0] > maxPacketDataLength)
      {
         forceVerify();

         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");
      }
   }

   /**
    * 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 > maxPacketDataLength)
         throw new OneWireException(
            "Length of packet requested exceeds page size");

      // see if this bank is general read/write
      if (!generalPurposeMemory)
         throw new OneWireException(
            "Current bank is not general purpose memory");

      // 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 * pageLength, 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
   {

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

   /**
    * 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");
   }

   //--------
   //-------- ScratchPad methods
   //--------

   /**
    * Read the scratchpad page of memory from a NVRAM device
    * This method reads and returns the entire scratchpad after the byte
    * offset regardless of the actual ending offset
    *
    * @param  readBuf       byte array to place read data into
    *                       length of array is always pageLength.
    * @param  offset        offset into readBuf to pug data
    * @param  len           length in bytes to read
    * @param  extraInfo     byte array to put extra info read into
    *                       (TA1, TA2, e/s byte)
    *                       length of array is always extraInfoLength.
    *                       Can be 'null' if extra info is not needed.
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void readScratchpad (byte[] readBuf, int offset, int len,
                               byte[] extraInfo)
      throws OneWireIOException, OneWireException
   {
      // select the device
      if (!ib.adapter.select(ib.address))
      {
         forceVerify();

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

      // build first block
      byte[] raw_buf = new byte [1 + extraInfoLength];

      raw_buf [0] = READ_SCRATCHPAD_COMMAND;

      System.arraycopy(ffBlock, 0, raw_buf, 1, extraInfoLength);

      // do the first block for TA1, TA2, and E/S
      ib.adapter.dataBlock(raw_buf, 0, 1 + extraInfoLength);

      // optionally extract the extra info
      if (extraInfo != null)
         System.arraycopy(raw_buf, 1, extraInfo, 0, extraInfoLength);

      // build the next block
      System.arraycopy(ffBlock, 0, readBuf, offset, len);

      // send second block to read data, return result
      ib.adapter.dataBlock(readBuf, offset, len);
   }

   /**
    * Write to the scratchpad page of memory a NVRAM device.
    *
    * @param  startAddr     starting address
    * @param  writeBuf      byte array containing data to write
    * @param  offset        offset into readBuf to place data
    * @param  len           length in bytes to write
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void writeScratchpad (int startAddr, byte[] writeBuf, int offset,
                                int len)
      throws OneWireIOException, OneWireException
   {

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

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

      // build block to send
      byte[] raw_buf = new byte [3 + len];

      raw_buf [0] = WRITE_SCRATCHPAD_COMMAND;
      raw_buf [1] = ( byte ) (startAddr & 0xFF);
      raw_buf [2] = ( byte ) (((startAddr & 0xFFFF) >>> 8) & 0xFF);

      System.arraycopy(writeBuf, offset, raw_buf, 3, len);

      // send block, return result
      ib.adapter.dataBlock(raw_buf, 0, len + 3);
   }

   /**
    * Copy the scratchpad page to memory.
    *
    * @param  startAddr     starting address
    * @param  len           length in bytes that was written already
    *
    * @throws OneWireIOException
    * @throws OneWireException
    */
   public void copyScratchpad (int startAddr, int len)
      throws OneWireIOException, OneWireException
   {

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

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

      // build block to send
      byte[] raw_buf = new byte [5];

      raw_buf [0] = COPY_SCRATCHPAD_COMMAND;
      raw_buf [1] = ( byte ) (startAddr & 0xFF);
      raw_buf [2] = ( byte ) (((startAddr & 0xFFFF) >>> 8) & 0xFF);
      raw_buf [3] = ( byte ) ((startAddr + len - 1) & 0x1F);
      raw_buf [4] = ( byte ) 0xFF;

      // send block (check copy indication complete)
      ib.adapter.dataBlock(raw_buf, 0, 5);

      if ((raw_buf [4] & 0x0F0) != 0)
      {
         forceVerify();

         throw new OneWireIOException("Copy scratchpad complete not found");
      }
   }

   //--------
   //-------- 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
         // 9-23-2003 shughes: added the check to see if the adapter is
         // currently at the ibutton's max speed.  If it isn't, we should
         // call the doSpeed() method, since the adapter might have
         // changed speeds.
         if (doSetSpeed || (ib.adapter.getSpeed()!=ib.getMaxSpeed()))
         {
            // 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;
      }
   }
}