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DS2502(3)		     One-Wire File System		     DS2502(3)

NAME
       DS2502 -	Add-Only Memory	(1 kBit)

       DS2502-E48, DS2502-UNW
	      -	48-bit Node Address Chip, UniqueWare Add-Only Memory (1	kBit)

       DS1982, DS1982U
	      -	Add-Only iButton (1 kBit), UniqueWare iButton (1 kBit)

SYNOPSIS
       EPROM add-only memory.

       09  [.]XXXXXXXXXXXX[XX][/[  memory  |  pages/page.[0-3|ALL] | address |
       crc8 | id | locator | r_address | r_id |	r_locator | type ]]

       89   [.]XXXXXXXXXXXX[XX][/[    mac_e    |    mac_fw    |	   memory    |
       pages/page.[0-3|ALL]  | project | address | crc8	| id | locator | r_ad-
       dress | r_id | r_locator	| type ]]

FAMILY CODE
       09     DS2502 DS1982

       89     DS2502-UNW DS2502-E48 DS1982U

SPECIAL	PROPERTIES
   mac_e mac_fw
       read-only, binary
       64 bit or 80 bit	media access control number. Unique, and unrelated  to
       the  1-wire address. It is apparently used for ethernet or FireWire ad-
       dressing, respectively.

   memory
       read-write, binary
       128 bytes of memory. Initially all bits are set to 1. Writing zero per-
       manently	alters the memory.

   pages/page.0	... pages/page.3 pages/page.ALL
       read-write, yes-no
       Memory  is split	into 4 pages of	32 bytes each.	ALL is an aggregate of
       the pages. Each page is accessed	sequentially.

   project
       read-only, binary
       32 bit project id. Constant 0x0000 for  ethernet	 and   0x00001128  for
       firewire. See Datasheets.

STANDARD PROPERTIES
   address
   r_address
       read-only, ascii
       The  entire  64-bit  unique  ID.	Given as upper case hexidecimal	digits
       (0-9A-F).
       address starts with the family code
       r address is the	address	in reverse order, which	is often used in other
       applications and	labeling.

   crc8
       read-only, ascii
       The  8-bit error	correction portion. Uses cyclic	redundancy check. Com-
       puted from the preceding	56 bits	of the unique ID number. Given as  up-
       per case	hexidecimal digits (0-9A-F).

   family
       read-only, ascii
       The  8-bit  family  code. Unique	to each	type of	device.	Given as upper
       case hexidecimal	digits (0-9A-F).

   id
   r_id
       read-only, ascii
       The 48-bit middle portion of the	unique ID number. Does not include the
       family code or CRC. Given as upper case hexidecimal digits (0-9A-F).
       r  id is	the id in reverse order, which is often	used in	other applica-
       tions and labeling.

   locator
   r_locator
       read-only, ascii
       Uses an extension of the	1-wire design from  iButtonLink	 company  that
       associated  1-wire  physical  connections with a	unique 1-wire code. If
       the connection is behind	a Link Locator the locator will	show a	unique
       8-byte number (16 character hexidecimal)	starting with family code FE.
       If  no  Link  Locator is	between	the device and the master, the locator
       field will be all FF.
       r locator is the	locator	in reverse order.

   present (DEPRECATED)
       read-only, yes-no
       Is the device currently present on the 1-wire bus?

   type
       read-only, ascii
       Part name assigned by Dallas Semi. E.g.	DS2401	Alternative  packaging
       (iButton	vs chip) will not be distiguished.

ALARMS
       None.

DESCRIPTION
   1-Wire
       1-wire is a wiring protocol and series of devices designed and manufac-
       tured by	Dallas Semiconductor, Inc. The bus is  a  low-power  low-speed
       low-connector scheme where the data line	can also provide power.

       Each  device  is	 uniquely and unalterably numbered during manufacture.
       There are a wide	variety	of devices, including memory, sensors  (humid-
       ity, temperature, voltage, contact, current), switches, timers and data
       loggers.	More complex devices (like thermocouple	sensors) can be	 built
       with  these  basic devices. There are also 1-wire devices that have en-
       cryption	included.

       The 1-wire scheme uses a	single bus master and multiple slaves  on  the
       same  wire.  The	bus master initiates all communication.	The slaves can
       be individually discovered and addressed	using their unique ID.

       Bus masters come	in a variety of	configurations including serial,  par-
       allel, i2c, network or USB adapters.

   OWFS	design
       OWFS  is	 a  suite of programs that designed to make the	1-wire bus and
       its devices easily accessible. The underlying priciple is to  create  a
       virtual filesystem, with	the unique ID being the	directory, and the in-
       dividual	properties of the device are represented as simple files  that
       can be read and written.

       Details	of  the	 individual slave or master design are hidden behind a
       consistent interface. The goal is to provide an easy set	of tools for a
       software	 designer  to create monitoring	or control applications. There
       are some	performance enhancements in the	implementation,	including data
       caching,	parallel access	to bus masters,	and aggregation	of device com-
       munication. Still the fundemental goal has been ease of use,  flexibil-
       ity and correctness rather than speed.

   DS2502 DS1982
       The  DS2502  (3)	 is used for write-once	incremental storage. It's main
       advantage is for	audit trails (i.e. a digital purse).

       The DS2502-E48 and DS2502-UNW are some of the UniqueWare	class  of  de-
       vices.  Some  of	 the  memory  was preprogramed at the factory. See the
       datasheet for specifics.	 The DS2502 , DS2505 , and  DS2506  differ  in
       their  function by the amount of	on-board memory	they possess. (The in-
       ternal protocols	are slightly different,	but the	 OWFS  system  handles
       this automatically.

ADDRESSING
       All  1-wire  devices are	factory	assigned a unique 64-bit address. This
       address is of the form:

       Family Code
	      8	bits

       Address
	      48 bits

       CRC    8	bits

       Addressing under	OWFS is	in hexidecimal,	of form:

	      01.123456789ABC

       where 01	is an example 8-bit family code, and 12345678ABC is an example
       48 bit address.

       The  dot	 is  optional,	and the	CRC code can included. If included, it
       must be correct.

DATASHEET
       http://pdfserv.maxim-ic.com/en/ds/DS2502.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS2502-E48.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS2502-UNW-DS2506S-UNW.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS1982-F3-DS1982-F5.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS1982U-DS1986U.pdf

SEE ALSO
   Programs
       owfs (1)	owhttpd	(1) owftpd (1)	owserver  (1)  owdir  (1)  owread  (1)
       owwrite (1) owpresent (1) owtap (1)

   Configuration and testing
       owfs (5)	owtap (1) owmon	(1)

   Language bindings
       owtcl (3) owperl	(3) owcapi (3)

   Clocks
       DS1427  (3)  DS1904(3)  DS1994  (3)  DS2404  (3)	DS2404S	(3) DS2415 (3)
       DS2417 (3)

   ID
       DS2401 (3) DS2411 (3) DS1990A (3)

   Memory
       DS1982 (3) DS1985 (3) DS1986 (3)	 DS1991	 (3)  DS1992  (3)  DS1993  (3)
       DS1995  (3)  DS1996  (3)	 DS2430A  (3) DS2431 (3) DS2433	(3) DS2502 (3)
       DS2506 (3) DS28E04 (3) DS28EC20 (3)

   Switches
       DS2405 (3) DS2406 (3) DS2408 (3)	DS2409 (3) DS2413 (3) DS28EA00 (3)

   Temperature
       DS1822 (3) DS1825 (3) DS1820 (3)	DS18B20	(3)  DS18S20  (3)  DS1920  (3)
       DS1921  (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
       EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3)	EDS0072	 (3)  MAX31826
       (3)

   Humidity
       DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)

   Voltage
       DS2450 (3)

   Resistance
       DS2890 (3)

   Multifunction (current, voltage, temperature)
       DS2436  (3)  DS2437  (3)	 DS2438	 (3)  DS2751 (3) DS2755	(3) DS2756 (3)
       DS2760 (3) DS2770 (3) DS2780 (3)	DS2781 (3) DS2788 (3) DS2784 (3)

   Counter
       DS2423 (3)

   LCD Screen
       LCD (3) DS2408 (3)

   Crypto
       DS1977 (3)

   Pressure
       DS2406 (3) TAI8570 EDS0066 (3) EDS0068 (3)

   Moisture
       EEEF (3)	DS2438 (3)

AVAILABILITY
       http://www.owfs.org

AUTHOR
       Paul Alfille (paul.alfille@gmail.com)

OWFS Manpage			     2003			     DS2502(3)

NAME | SYNOPSIS | FAMILY CODE | SPECIAL PROPERTIES | STANDARD PROPERTIES | ALARMS | DESCRIPTION | ADDRESSING | DATASHEET | SEE ALSO | AVAILABILITY | AUTHOR

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