DS2760(3)						       One-Wire File System							 DS2760(3)

NAME

       DS2780 - Stand-alone Fuel Gauge IC
       DS2788 - Stand-alone Fuel Gauge with LED Drivers

SYNOPSIS

   Temperature Voltage Current Memory and Switch.
       32 [.]XXXXXXXXXXXX[XX][/[ lock.[0-1|ALL] | memory | pages/page.[0-1|ALL] | PIO | sensed | temperature | vbias | vis | volt | volthours |
       aef | chgtf | ds | learnf | pmod | porf | rnaop | sef | uven | uvf |
       address | crc8 | id | locator | r_address | r_id | r_locator | type ]]

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

FAMILY CODE

       32

SPECIAL PROPERTIES

   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 DS2680 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 DS2780 to read the Seebeck voltage and the reference temperature. Since the type interpretation of the val-
       ues 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 temper-
       ature read at the chip. The typeX/temperature value is at the thermocouple junction, probably remote from the chip.

OBSCURE PROPERTIES

   aef chgtf dc learnf pmod porf rnaop sef uven uvf
       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.

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 (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 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.

   DS2780
       The DS2780 (3) is a battery charging controller. It has elaborate algorithms for estimating battery capacity.

       A number of interesting devices can be built with the DS2780 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/DS2780.pdf
       http://pdfserv.maxim-ic.com/en/ds/DS2788.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)

OWFS Manpage							       2003								 DS2760(3)