com.dalsemi.onewire.container
Interface MemoryBank

All Known Subinterfaces:

OTPMemoryBank, PagedMemoryBank

public interface MemoryBank

Memory bank interface class for basic memory communication with iButtons (or 1-Wire devices). The method getMemoryBanks in all 1-Wire Containers (OneWireContainer) returns an Enumeration of this interface to be used to read or write it's memory. If the 1-Wire device does not have memory or the memory is non-standard, then this enumeration may be empty. A MemoryBank returned from this method may also implement the PagedMemoryBank, or OTPMemoryBank interfaces, to provide additional functionality.

The MemoryBank methods can be organized into the following categories:

• Information
  • getBankDescription
  • getSize
  • getStartPhysicalAddress
  • isGeneralPurposeMemory
  • isReadWrite
  • isWriteOnce
  • isReadOnly
  • isNonVolatile
  • needsProgramPulse
  • needsPowerDelivery
• Options
  • setWriteVerification
• I/O
  • read
  • write

Usage

Example 1

Display some features of MemoryBank instance 'mb':

 
  if (mb.isWriteOnce())
     System.out.println("MemoryBank is write-once");
 
  if (mb.needsProgramPulse())
     System.out.println("MemoryBank requires program-pulse to write");
  

Example 2

Write the entire contents of a MemoryBank instance 'mb' with zeros:

 
  byte[] write_buf = new byte[mb.getSize()];
  for (int i = 0; i < write_buf.length; i++)
      write_buf[i] = (byte)0;
 
  mb.write(0, write_buf, 0, write_buf.length);
  

Example 3

Read the entire contents of a MemoryBank instance 'mb':

 
  byte[] read_buf = new byte[mb.getSize()];

  mb.read(0, false, read_buf, 0, read_buf.length);
  

Version:

0.00, 28 Aug 2000

Author:

DS

See Also:

PagedMemoryBank, OTPMemoryBank, OneWireContainer04, OneWireContainer06, OneWireContainer08, OneWireContainer09, OneWireContainer0A, OneWireContainer0B, OneWireContainer0C, OneWireContainer0F, OneWireContainer12, OneWireContainer13, OneWireContainer14, OneWireContainer18, OneWireContainer1A, OneWireContainer1D, OneWireContainer20, OneWireContainer21, OneWireContainer23

Method Summary

String	getBankDescription() Gets a string description of this memory bank.
int	getSize() Gets the size of this memory bank in bytes.
int	getStartPhysicalAddress() Gets the starting physical address of this bank.
boolean	isGeneralPurposeMemory() Checks to see if this memory bank is general purpose user memory.
boolean	isNonVolatile() Checks to see if this memory bank is non-volatile.
boolean	isReadOnly() Checks to see if this memory bank is read only.
boolean	isReadWrite() Checks to see if this memory bank is read/write.
boolean	isWriteOnce() Checks to see if this memory bank is write once such as with EPROM technology.
boolean	needsPowerDelivery() Checks to see if this memory bank requires 'PowerDelivery' in order to write.
boolean	needsProgramPulse() Checks to see if this memory bank requires a 'ProgramPulse' in order to write.
void	read(int startAddr, boolean readContinue, byte[] readBuf, int offset, int len) Reads memory in this bank with no CRC checking (device or data).
void	setWriteVerification(boolean doReadVerf) Sets or clears write verification for the write method.
void	write(int startAddr, byte[] writeBuf, int offset, int len) Writes memory in this bank.

Method Detail

getBankDescription

public String getBankDescription()

Gets a string description of this memory bank.

Returns:

the memory bank description

isGeneralPurposeMemory

public boolean isGeneralPurposeMemory()

Checks to see if this memory bank is general purpose user memory. If it is NOT then it may be Memory-Mapped and writing values to this memory may affect the behavior of the 1-Wire device.

Returns:

true if this memory bank is general purpose

getSize

public int getSize()

Gets the size of this memory bank in bytes.

Returns:

number of bytes in current memory bank

isReadWrite

public boolean isReadWrite()

Checks to see if this memory bank is read/write.

Returns:

true if this memory bank is read/write

isWriteOnce

public boolean isWriteOnce()

Checks to see if this memory bank is write once such as with EPROM technology.

Returns:

true if this memory bank can only be written once

isReadOnly

public boolean isReadOnly()

Checks to see if this memory bank is read only.

Returns:

true if this memory bank can only be read

isNonVolatile

public boolean isNonVolatile()

Checks to see if this memory bank is non-volatile. Memory is non-volatile if it retains its contents even when removed from the 1-Wire network.

Returns:

true if this memory bank is non volatile

needsProgramPulse

public boolean needsProgramPulse()

Checks to see if this memory bank requires a 'ProgramPulse' in order to write.

Returns:

true if writing to this memory bank requires a 'ProgramPulse' from the 1-Wire Adapter.

See Also:

DSPortAdapter

needsPowerDelivery

public boolean needsPowerDelivery()

Checks to see if this memory bank requires 'PowerDelivery' in order to write.

Returns:

true if writing to this memory bank requires 'PowerDelivery' from the 1-Wire Adapter

See Also:

DSPortAdapter

getStartPhysicalAddress

public int getStartPhysicalAddress()

Gets the starting physical address of this bank. Physical banks are sometimes sub-divided into logical banks due to changes in attributes. Note that this method is for information only. The read and write methods will automatically calculate the physical address when writing to a logical memory bank.

Returns:

physical starting address of this logical bank

setWriteVerification

public void setWriteVerification(boolean doReadVerf)

Sets or clears write verification for the write method.

Parameters:

doReadVerf - true (default) verify write in 'write', false don't verify write (used on Write-Once bit manipulation)

See Also:

OTPMemoryBank

read

public void read(int startAddr,
                 boolean readContinue,
                 byte[] readBuf,
                 int offset,
                 int len)
          throws OneWireIOException,
                 OneWireException

Reads memory in this 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 recommended that the data contain some kind of checking (CRC) like in the readPagePacket method in the PagedMemoryBank interface. Some 1-Wire devices provide thier own CRC as in readPageCRC also found in the PagedMemoryBank interface. The readPageCRC method is not supported on all memory types, see hasPageAutoCRC in the same interface. If neither is an option then this method could be called more then once to at least verify that the same data is read consistently. The readContinue parameter is used to eliminate the overhead in re-accessing a part already being read from. For example, if pages 0 - 4 are to be read, readContinue would be set to false for page 0 and would be set to true for the next four calls.

Note: Using readContinue = true can only be used if the new read continuous where the last one led off and it is inside a 'beginExclusive/endExclusive' block.

Parameters:

startAddr - starting address

readContinue - true then device read is continued without re-selecting

readBuf - location for data read

offset - offset into readBuf to place data

len - length in bytes to read

Throws:

OneWireIOException - on a 1-Wire communication error such as no device present. This could be caused by a physical interruption in the 1-Wire Network due to shorts or a newly arriving 1-Wire device issuing a 'presence pulse'.

OneWireException - on a communication or setup error with the 1-Wire adapter

write

public void write(int startAddr,
                  byte[] writeBuf,
                  int offset,
                  int len)
           throws OneWireIOException,
                  OneWireException

Writes memory in this bank. It is recommended that a structure with some built in error checking is used to provide data integrity on read. The method writePagePacket found in the PagedMemoryBank interface, which automatically wraps the data in a length and CRC, could be used for this purpose.

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.

Parameters:

startAddr - starting address

writeBuf - data to write

offset - offset into writeBuf to get data

len - length in bytes to write

Throws:

OneWireIOException - on a 1-Wire communication error such as no device present or a read back verification fails. This could be caused by a physical interruption in the 1-Wire Network due to shorts or a newly arriving 1-Wire device issuing a 'presence pulse'.

OneWireException - on a communication or setup error with the 1-Wire adapter