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NAME

       DS2751 - Multichemistry Battery Fuel Gauge

SYNOPSIS

   Temperature Voltage, Current, Memory, and Switch.
       51  [.]XXXXXXXXXXXX[XX][/[  amphours  |  current | currentbias | lock.[0-1|ALL] | memory |
       pages/page.[0-1|ALL] | PIO | sensed | temperature | typeX/range_low |  typeX/range_high  |
       typeX/temperature | vbias | vis | volt | volthours |
       defaultpmod | pmod | por | uven |
       address | crc8 | id | locator | r_address | r_id | r_locator | type ]]

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

FAMILY CODE

       51

SPECIAL PROPERTIES

   amphours
       read-write, floating point
       Accumulated amperage read by current sensor. Units are in Amp-hr (Assumes 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.[0-1|ALL]
       read-write, yes-no
       Lock  either  of the two 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 reserved or  special  use.
       User space is the page area.
       See the DATASHEET for a full memory map.

   pages/pages.[0-1|ALL]
       read-write, binary Two 16 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 implementation 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 voltage 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 DS2760 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  conversion.  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  temperature  read  at  the   chip.   The
       typeX/temperature value is at the thermocouple junction, probably remote from the chip.

OBSCURE PROPERTIES

   pmod por uven
       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 corresponds 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.  Computed  from  the
       preceding  56  bits of the unique ID number. Given as upper 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 applications 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  manufactured  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 (humidity, 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
       encryption 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, parallel,  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 individual 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
       communication.  Still  the  fundemental  goal  has  been  ease  of  use,  flexibility  and
       correctness rather than speed.

   DS2751
       The DS2751 (3) is battery charging controllers similar to the DS2760 (3)

       A  number of interesting devices can be built with the DS2751 (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/DS2751.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)

   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)

AVAILABILITY

       http://www.owfs.org

AUTHOR

       Paul Alfille (paul.alfille@gmail.com)