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DS2437(3)		     One-Wire File System		     DS2437(3)

NAME
       DS2437 -	Smart Battery Monitor

SYNOPSIS
       Temperature Voltages and	Memory.

       1E  [.]XXXXXXXXXXXX[XX][/[  current  | date | disconnect/date | discon-
       nect/udate   |	endcharge/date	 |   endcharge/udate   |   Ienable   |
       pages/page.[0-7|ALL] | temperature | udate | VAD	| VDD |	address	| crc8
       | id | locator |	r_address | r_id | r_locator | type ]]

FAMILY CODE
       1E

SPECIAL	PROPERTIES
   date
       read-write, ascii
       26 character date representation	of the counter value. Increments  once
       per second.
       Setting date to a null string will put the current system time.
       Accepted	date formats are:
	 Sat[urday] March 12 12:23:59 2001
	 Apr[il] 4 9:34:56 2002
	 3/23/04 23:34:57
	 current locale	setting	(your system's format)

   current
       read-only, integer
       Current	 reading.  Actual  current  depends  on	 Rsens	resistor  (see
       datasheet).
       The formula for current is I = current /(4096*Rsens)
       with units in Amps and Ohms.
       Current measurement will	be temporarily enabled (see Ienable )  if  not
       currently enabled (pun intended)	for this reading.

   disconnect/date
       read-write, ascii
       26  character  date  representation of the disconnect/udate value. Time
       when the	battery	pack waws removed from the charger. Format is the same
       as the date property.

   disconnect/udate
       read-write, unsigned integer
       Representation of disconnect/date as a number. See udate	for details.

   endcharge/date
       read-write, ascii
       26  character  date representation of the endcharge/udate value.	Format
       is the same as the date property.

   endcharge/udate
       read-write, unsigned integer
       Representation of endcharge/date	as a number. See udate for details.

   Ienable
       read-write, unsigned integer
       Status of current monitoring. When enabled,  current  sensing  is  per-
       formed 36.41 times/second. Values of Ienable are:

       0      no current conversion

       1      current conversion enabled

       2      current conversion and accumulation

       3      current conversion and accumulation with EEPROM backup

   pages/page.0	... pages/page.7 pages/page.ALL
       read-write, binary
       Memory  is  split  into 8 pages of 8 bytes each.	Only the pages 3-7 are
       really available, and some of that appears  to  be  reserved.  See  the
       datasheet for details.
       ALL is an aggregate of the pages. Each page is accessed sequentially.

   temperature
       read-only, floating point
       Temperature  read  by the chip at high resolution (~13 bits). Units are
       selected	from the invoking command line.	See owfs(1) or owhttpd(1)  for
       choices.	Default	is Celsius.  Conversion	takes ~20 msec.

   udate
       read-write, unsigned integer
       Time represented	as a number.  udate increments once per	second.
       Usually set to unix time	standard: number of seconds since Jan 1, 1970.
       The date	field will be the unix representation (ascii  text)  of	 udate
       and setting either will change the other.

   VAD VDD
       read-only, floating point
       Voltage	read  (~10 bits) at the	one of the chip's two supply voltages.
       Range VDD= 2.4V to 10V, VAD=1.5 to 10V.

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.

   DS2437
       The DS2437 (3) is an obsolete version of	the DS2438 (3)	battery	 chip.
       Current	sensing	is available, but not implemented. The major advantage
       compared	to the DS2436 is that two voltages can be read,	allowing  cor-
       recting circuit nmeasurements to	supply voltage and temperature.	A bet-
       ter comparison is the DS276x family of chips.

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/DS2437.pdf
       http://pdfserv.maxim-ic.com/en/an/humsensor.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			     DS2437(3)

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

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