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DS28EA00(3)		     One-Wire File System		   DS28EA00(3)

NAME
       DS28EA00	- 1-Wire Digital Thermometer with Sequence Detect and PIO

SYNOPSIS
       Thermometer, PIO	and Chain.

       42  [.]XXXXXXXXXXXX[XX][/[ fasttemp | temperature | temperature9	| tem-
       perature10 | temperature11 | temperature12 die |	 power	|  temphigh  |
       templow | PIO.A|B|ALL.BYTE | latch.A|B|ALL.BYTE | sensed.A|B|ALL.BYTE

       address | crc8 |	id | locator | r_address | r_id	| r_locator | type ]]

FAMILY CODE
       42

SPECIAL	PROPERTIES
   power
       read-only,yes-no
       Is  the chip powered externally (=1) or from the	parasitically from the
       data bus	(=0)?

TEMPERATURE PROPERTIES
   temperature
       read-only, floating point
       Measured	temperature with 12 bit	resolution.

   temperature9	temperature10 temperature11 temperature12
       read-only, floating point Measured temperature at 9 to 12  bit  resolu-
       tion.  There  is	 a tradeoff of time versus accuracy in the temperature
       measurement.

   fasttemp
       read-only, floating point
       Equivalent to temperature9

PIO PROPERTIES
   PIO.A|B|ALL|BYTE
       read-write, yes-no
       Two channels of sensors/switches. We use	the logical raqther than elet-
       rical  interpretation:  0=off  (non-conducting)	1=on (conducting -- to
       ground)

       The PIO channels	are alternatively used for the sequence-detect (chain)
       mode.

       Reading sensed gives the	inverse	value of the cooresponding PIO.

       Reading	PIO gives the actual pin values. Use the latch property	to see
       how the pin is set.

   latch.A|B|ALL|BYTE
       read-only, yes-no
       Set (intended) va;ue of the PIO pins.

   sensed.A|B|ALL|BYTE
       read-only, yes-no
       Actual logical level at the PIO pins.

SPECIAL	PROPERTIES
   power
       read-only,yes-no
       Is the chip powered externally (=1) or from the parasitically from  the
       data bus	(=0)?

TEMPERATURE ALARM LIMITS
       When  the device	exceeds	either temphigh	or templow temperature thresh-
       old the device is in the	alarm state, and will appear in	the alarm  di-
       rectory.	 This  provides	 an easy way to	poll for temperatures that are
       unsafe, especially if simultaneous temperature conversion is done.

       Units for the temperature alarms	are in the same	temperature scale that
       was set for temperature measurements.

       Temperature  thresholds	are  stored in non-volatile memory and persist
       until changed, even if power is lost.

   temphigh
       read-write, integer
       Shows or	sets the lower limit for the high temperature alarm state.

   templow
       read-write, integer
       Shows or	sets the upper limit for the low temperature alarm state.

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.

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.

   DS28EA00
       The DS28EA00 (3)	is one of several available  1-wire  temperature  sen-
       sors. It	is the replacement for the DS18S20 (3) Alternatives are	DS1822
       (3) as well as temperature/vlotage measurements in the DS2436  (3)  and
       DS2438 (3).  For	truly versatile	temperature measurements, see the pro-
       tean DS1921 (3) Thermachron (3).
       The DS28EA00 has	special	switch/sequence	detect properties. In sequence
       mode, the PIO pins are daisy-chained to the next	DS28EA00, allowing the
       system to step through the physical sequence of the DS28EA00s.

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/DS28EA00.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			   DS28EA00(3)

NAME | SYNOPSIS | FAMILY CODE | SPECIAL PROPERTIES | TEMPERATURE PROPERTIES | PIO PROPERTIES | SPECIAL PROPERTIES | TEMPERATURE ALARM LIMITS | STANDARD PROPERTIES | DESCRIPTION | ADDRESSING | DATASHEET | SEE ALSO | AVAILABILITY | AUTHOR

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