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DS2755(3)		     One-Wire File System		     DS2755(3)

NAME
       DS2755, DS2756 -	Multichemistry Battery Fuel Gauge

SYNOPSIS
   Temperature Voltage,	Current, Memory, and Switch.
       35 [.]XXXXXXXXXXXX[XX][/[ alarm_set/[volthigh|voltlow|temphigh|templow]
       | lock.[0-2|ALL]	| memory | pages/page.[0-2|ALL]	| PIO |	sensed |  tem-
       perature	| vbias	| vis |	volt | volthours |
       defaultpmod  |  pie0  |	pie1 | rnaop | ios | uben | ovd	| pmod | por |
       uven |
       address | crc8 |	id | locator | r_address | r_id	| r_locator | type ]]

   Thermocouple
       35   [.]XXXXXXXXXXXX[XX][/[    temperature    |	  typeX/range_low    |
       typeX/range_high	| typeX/temperature

FAMILY CODE
       35

SPECIAL	PROPERTIES
   alarm_set/templow alarm_set/temphigh
       read-write, integer
       High and	low alarm settings for temperature

   alarm_set/voltlow alarm_set/volthigh
       read-write, floating point
       High and	low alarm settings for volts

   lock.[0-2|ALL]
       read-write, yes-no
       Lock any	of the three eprom pages to prevent further writes. Apparently
       setting lock is permanent.

   memory
       read-write, binary
       Access to the full 256 byte memory range. Much of  this	space  is  re-
       served or special use. User space is the	page area.
       See the DATASHEET for a full memory map.

   pages/pages.[0-2|ALL]
       read-write,  binary Three 32 byte areas of memory for user application.
       The lock	property can prevent further alteration.
       NOTE that the page property is different	from the common	OWFS implemen-
       tation in that all of memory is not accessible.

   PIO
       write-only, yes-no
       Controls	the PIO	pin allowing external switching.
       Writing	"1"  turns  the	PIO pin	on (conducting). Writing "0" makes the
       pin non-conducting.  The	logical	state of the voltage can be read  with
       the  sensed property. This will reflect the current voltage at the pin,
       not the value sent to PIO
       Note also that PIO will also be altered	by  the	 power-status  of  the
       DS2670 See the datasheet	for details.

   sensed
       read-only, yes-no
       The  logical voltage at the PIO pin. Useful only	if the PIO property is
       set to "0" (non-conducting).
       Value will be 0 or 1 depending on the voltage threshold.

   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 is continuous.

   vbias
       read-write, floating point
       Fixed offset applied to each vis	measurement. Used  for	the  volthours
       value. Units are	in Volts.
       Range -2.0mV to 2.0mV

   vis
       read-only, floating point
       Current	sensor reading (unknown	external resistor). Measures the volt-
       age gradient between the	Vis pins. Units	are in Volts
       The vis readings	are integrated over  time  to  provide	the  volthours
       property.
       The  current  reading is	derived	from vis assuming the internal 25 mOhm
       resistor	is employed. There is no way to	know this through software.

   volt
       read-only, floating point
       Voltage read at the voltage sensor;. This  is  separate	from  the  vis
       voltage that is used for	current	measurement. Units are Volts
       Range is	between	0 and 4.75V

   volthours
       read-write, floating point
       Integral	of vis - vbias over time. Units	are in volthours

THERMOCOUPLE
   typeX/
       directory
       Thermocouple  circuit  using the	DS2755 to read the Seebeck voltage and
       the reference temperature. Since	the type interpretation	of the	values
       read depends on the type	of thermocouple, the correct directory must be
       chosen. Supported thermocouple types include types B, E,	J, K, N, R,  S
       and T.

   typeX/range_low typeX/ranges_high
       read-only, flaoting point
       The  lower  and	upper  temperature  supported by this thermocouple (at
       least by	the conversion routines). In the globally  chosen  temperature
       units.

   typeX/temperature
       read-only, floating point
       Thermocouple  temperature.  Requires  a voltage and temperature conver-
       sion. Returned in globally chosen temperature units.
       Note: there are two types of  temperature  measurements	possible.  The
       temperature value in the	main device directory is the reference temper-
       ature read at the chip. The typeX/temperature value is at  the  thermo-
       couple junction,	probably remote	from the chip.

OBSCURE	PROPERTIES
   pmod	por uven pie0 pie1 ios uben ovd	rnaop
       varies, yes-no
       Bit  flags corresponding	to various battery management functions	of the
       chip. See the DATASHEET for details of the identically named entries.
       In general, writing "0" corresponds to a	0 bit value, and non-zero cor-
       responds	to a 1 bit value.

   defaultpmod
       read-write, yes-no
       Default power-on	state for the corresponding properties.

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
       Temperature and voltage.

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.

   DS2755 DS2756
       The  DS2755 (3) and DS2756 (3) are battery charging controllers similar
       to the DS2751 (3) except	no internal resistor option and	a larger  EEP-
       ROM memory.

       The DS2756 (3) adds suspend modes ( pie0	pie1 ) to the DS2755 (3)

       A  number  of  interesting devices can be built with the	DS2755 (3) and
       DS2756 (3) including thermocouples. Support for thermocouples in	 built
       into  the  software, using the embedded thermister as the cold junction
       temperature.

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/DS2755.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS2756.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			     DS2755(3)

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

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