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DS2770(3)		     One-Wire File System		     DS2770(3)

NAME
       DS2770 -	Battery	Monitor	and Charge Controller

SYNOPSIS
   Temperature Voltage Current Memory and Switch.
       2E   [.]XXXXXXXXXXXX[XX][/[   amphours	|   current  |	currentbias  |
       lock.[0-2|ALL] |	memory | pages/page.[0-2|ALL] |	PIO | sensed | temper-
       ature | vbias | vis | volt | volthours |
       charge  | cini |	cstat0 | cstat1	| ctype	| defaultpmod |	pmod | refresh
       | timer |
       address | crc8 |	id | locator | r_address | r_id	| r_locator | type ]]

   Thermocouple
       2E   [.]XXXXXXXXXXXX[XX][/[    temperature    |	  typeX/range_low    |
       typeX/range_high	| typeX/temperature

FAMILY CODE
       2E

SPECIAL	PROPERTIES
   amphours
       read-write, floating point
       Accumulated  amperage  read by current sensor. Units are	in Amp-hr (As-
       sumes internal 25mOhm resistor).	Derived	from volthours / Rinternal.
       Formally	amphours is the	integral of current - currentbias over time.

   current
       read-only, floating point
       Current reading.	Units are in Amp (Assumes internal 25 mOhm  resistor).
       Derived from vis	/ Rinternal.

   currentbias
       read-write, floating point
       Fixed  offset applied to	each current measurement. Used in the amphours
       value. Assumes internal 25mOhm resistor.	Units are Amp and  range  from
       -.08A to	.08A.
       Derived from vbias / Rinternal.

   lock.[0-2|ALL]
       read-write, yes-no
       Lock  either of the three eprom pages to	prevent	further	writes.	Appar-
       ently 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 Two 16 byte  and one 8 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	DS2770 (3) 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
   charge
       write-only, yes-no
       Trigger the start (1) or	stop(0)	of charging. see the DATASHEET for de-
       tails.

   cini	cstat0 cstat1 ctype pmod
       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.

   refresh
       write-only, yes-no
       Writing anything	to this	file causes a refresh of parameters. See the

   timer
       read-write, floating point
       A charge	timer in units of hours.  See the DATASHEET for	details.

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.

   DS2770
       The DS2770 (3) is a  battery  charging  controller.  It	has  elaborate
       charge estimation algorithms built in.

       A  number of interesting	devices	can be built with the DS2770 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/DS2770.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			     DS2770(3)

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

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