Interface PagedMemoryBank
- All Superinterfaces:
MemoryBank
- All Known Subinterfaces:
OTPMemoryBank
- All Known Implementing Classes:
MemoryBankNVCRCPW
,MemoryBankScratchCRCPW
,MemoryBankScratchSHAEE
,MemoryBankSHAEE
Paged Memory bank interface for iButtons (or 1-Wire devices) with page based
memory. This interface extents the base functionality of the super-interface
MemoryBank
by providing
paged based services.
This interface has methods to read and write a packet structure called the UDP (Universal Data Packet). This structure has a length byte, data, and an inverted CRC16. See Maxim Integrated Products Application Note 114 for details: http://dbserv.maxim-ic.com/appnotes.cfm?appnote_number=114
The MemoryBank methods can be organized into the following categories:
- Information
- I/O
Usage
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Example 1
Display some features of PagedMemoryBank instance 'pmb':System.out.print("PagedMemoryBank has: " + pmb.getNumberPages() + " pages of length "); System.out.print(pbank.getPageLength() + " bytes "); if (bank.isGeneralPurposeMemory()) System.out.print("giving " + pbank.getMaxPacketDataLength() + " bytes Packet data payload"); System.out.println(); if (pbank.hasPageAutoCRC()) System.out.print("PagedMemoryBank has device generated CRC");
Example 2
Write a packet into the first page of a PagedMemoryBank instance 'pmb':byte[] write_buf = new byte[pmb.getMaxPacketDataLength()]; for (int i = 0; i < write_buf.length; i++) write_buf[i] = (byte)0; mb.writePagePacket(0, write_buf, 0, write_buf.length);
Example 3
Read all of the pages of a PagedMemoryBank instance 'pmb' with device CRC verification:byte[] read_buf = new byte[pmb.getPageLength()]; if (pmb.hasAutoCRC()) { // loop to read each page with CRC for (int pg = 0; pg < pmb.getNumberPages(); pg++) { // use 'readContinue' argument to only access device on first page pmb.readPageCRC(pg, (pg == 0), read_buf, 0); // do something with data in read_buf ... } } else System.out.println("PagedMemoryBank does not support device generated CRC");
- See Also:
-
MemoryBank
OTPMemoryBank
OneWireContainer04
OneWireContainer06
OneWireContainer08
OneWireContainer09
OneWireContainer0A
OneWireContainer0B
OneWireContainer0C
OneWireContainer0F
OneWireContainer12
OneWireContainer13
OneWireContainer14
OneWireContainer18
OneWireContainer1A
OneWireContainer1D
OneWireContainer20
OneWireContainer21
OneWireContainer23
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Method Summary
Modifier and TypeMethodDescriptionGets a string description of what is contained in the Extra Information returned when reading pages in this memory bank.int
Gets the length in bytes of extra information that is read when reading a page in this memory bank.int
Gets Maximum data page length in bytes for a packet read or written in this memory bank.int
Gets the number of pages in this memory bank.int
Gets raw page length in bytes in this memory bank.boolean
Checks to see if this memory bank's pages deliver extra information outside of the normal data space, when read.boolean
Checks to see if this memory bank's pages can be read with the contents being verified by a device generated CRC.void
readPage
(int page, boolean readContinue, byte[] readBuf, int offset) Reads a page in this memory bank with no CRC checking (device or data).void
readPage
(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) Reads a page in this memory bank with extra information with no CRC checking (device or data).void
readPageCRC
(int page, boolean readContinue, byte[] readBuf, int offset) Reads a complete memory page with CRC verification provided by the device.void
readPageCRC
(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) Reads a complete memory page with CRC verification provided by the device with extra information.int
readPagePacket
(int page, boolean readContinue, byte[] readBuf, int offset) Reads a Universal Data Packet.int
readPagePacket
(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) Reads a Universal Data Packet and extra information.void
writePagePacket
(int page, byte[] writeBuf, int offset, int len) Writes a Universal Data Packet.Methods inherited from interface com.dalsemi.onewire.container.MemoryBank
getBankDescription, getSize, getStartPhysicalAddress, isGeneralPurposeMemory, isNonVolatile, isReadOnly, isReadWrite, isWriteOnce, needsPowerDelivery, needsProgramPulse, read, setWriteVerification, write
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Method Details
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getNumberPages
int getNumberPages()Gets the number of pages in this memory bank. The page numbers are then always 0 to (getNumberPages() - 1).- Returns:
- number of pages in this memory bank
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getPageLength
int getPageLength()Gets raw page length in bytes in this memory bank.- Returns:
- page length in bytes in this memory bank
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getMaxPacketDataLength
int getMaxPacketDataLength()Gets Maximum data page length in bytes for a packet read or written in this memory bank. See thereadPagePacket
andwritePagePacket
methods. This method is only useful if this memory bank is general purpose memory.- Returns:
- max packet page length in bytes in this memory bank
- See Also:
-
hasPageAutoCRC
boolean hasPageAutoCRC()Checks to see if this memory bank's pages can be read with the contents being verified by a device generated CRC. This is used to see if thereadPageCRC
method can be used.- Returns:
true
if this memory bank can be read with self generated CRC- See Also:
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hasExtraInfo
boolean hasExtraInfo()Checks to see if this memory bank's pages deliver extra information outside of the normal data space, when read. Examples of this may be a redirection byte, counter, tamper protection bytes, or SHA-1 result. If this method returns true then the methods with an 'extraInfo' parameter can be used:readPage
,readPageCRC
, andreadPagePacket
.- Returns:
true
if reading the this memory bank's pages provides extra information- Since:
- 1-Wire API 0.01
- See Also:
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getExtraInfoLength
int getExtraInfoLength()Gets the length in bytes of extra information that is read when reading a page in this memory bank.- Returns:
- number of bytes in Extra Information read when reading pages from this memory bank
- See Also:
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getExtraInfoDescription
String getExtraInfoDescription()Gets a string description of what is contained in the Extra Information returned when reading pages in this memory bank.- Returns:
- extra information description.
- See Also:
-
readPage
void readPage(int page, boolean readContinue, byte[] readBuf, int offset) throws OneWireIOException, OneWireException Reads a page in this memory 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 thereadPagePacket
method or have the 1-Wire device provide the CRC as inreadPageCRC
. However device CRC generation is not supported on all memory types, seehasPageAutoCRC
. 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 continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to read packet fromreadContinue
-true
then device read is continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place data- Throws:
OneWireIOException
- on a 1-Wire communication error such as no 1-Wire 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
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readPage
void readPage(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) throws OneWireIOException, OneWireException Reads a page in this memory bank with extra information 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 thereadPagePacket
method or have the 1-Wire device provide the CRC as inreadPageCRC
. However device CRC generation is not supported on all memory types, seehasPageAutoCRC
. 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 continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to read packet fromreadContinue
-true
then device read is continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place dataextraInfo
- location for extra info read- Throws:
OneWireIOException
- on a 1-Wire communication error such as no 1-Wire 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- See Also:
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readPagePacket
int readPagePacket(int page, boolean readContinue, byte[] readBuf, int offset) throws OneWireIOException, OneWireException Reads 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. The structure is used by this method to verify the data but only the data payload is returned. 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.See Maxim Integrated Products Application Note 114 for details: http://dbserv.maxim-ic.com/appnotes.cfm?appnote_number=114
Note: Using readContinue = true can only be used if the new read continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to read packet fromreadContinue
-true
true then device read is continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place data- Returns:
- number of data bytes read from the device and saved to readBuf at the provided offset
- Throws:
OneWireIOException
- on a 1-Wire communication error such as an invalid CRC16 or length found in the packet. 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'. It could also be caused due to the device page not containing a valid packet.OneWireException
- on a communication or setup error with the 1-Wire adapter- See Also:
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readPagePacket
int readPagePacket(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) throws OneWireIOException, OneWireException Reads a Universal Data Packet and extra information. See the methodreadPagePacket
for a description of the packet structure. 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 continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to read packet fromreadContinue
-true
then device read is continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place dataextraInfo
- location for extra info read- Returns:
- number of data bytes read from the device and written to readBuf at the offset.
- Throws:
OneWireIOException
- on a 1-Wire communication error such as an invalid CRC16 or length found in the packet. 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'. It could also be caused due to the device page not containing a valid packet.OneWireException
- on a communication or setup error with the 1-Wire adapter- See Also:
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writePagePacket
void writePagePacket(int page, byte[] writeBuf, int offset, int len) throws OneWireIOException, OneWireException Writes a Universal Data Packet. See the methodreadPagePacket
for a description of the packet structure.- Parameters:
page
- page number to write packet towriteBuf
- data to writeoffset
- offset into writeBuf where data to write islen
- number of bytes to write with a max ofgetMaxPacketDataLength
elements- Throws:
OneWireIOException
- on a 1-Wire communication error such as read verification error on write. 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'. It could also be caused due to the device page being write protected.OneWireException
- on a communication or setup error with the 1-Wire adapter- See Also:
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readPageCRC
void readPageCRC(int page, boolean readContinue, byte[] readBuf, int offset) throws OneWireIOException, OneWireException Reads a complete memory page with CRC verification provided by the device. Not supported by all devices. 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 continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to readreadContinue
-true
true then device read is continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place data- Throws:
OneWireIOException
- on a 1-Wire communication error such as an invalid CRC read from device. 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- See Also:
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readPageCRC
void readPageCRC(int page, boolean readContinue, byte[] readBuf, int offset, byte[] extraInfo) throws OneWireIOException, OneWireException Reads a complete memory page with CRC verification provided by the device with extra information. Not supported by all devices. 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 continues where the last one left off and it is inside a 'beginExclusive/endExclusive' block.
- Parameters:
page
- page number to readreadContinue
-true
true then device read is issued without continued without re-selectingreadBuf
- location for data readoffset
- offset into readBuf to place dataextraInfo
- location for extra info read- Throws:
OneWireIOException
- on a 1-Wire communication error such as an invalid CRC read from device. 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- See Also:
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