DS2760(3)

📦 version 3.2_p4, in alpine 3.24, debian bookworm, debian trixie, fedora 43, fedora 44, nixos 26.05, nixpkgs unstable, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 DS2760(3) — bestie, it's the One-Wire File System page 💖

okay so this is a page from the One-Wire File System manual (that's the owfs crew, section 3 of the man pages, and the page itself is filed as DS2760). grab a snack, we're getting into it 🍓

✨ NAME ✨

DS2781 — Stand-alone Fuel Gauge IC 👑

🌸 SYNOPSIS 🌸

Temperature Voltage Current Memory and Switch.

3D [.]XXXXXXXXXXXX[XX][/[ lock.[0-1|ALL] | memory | pages/page.[0-1|ALL]
| PIO | sensed | temperature | vbias | vis | vis_avg | vis_offset | volt
| volthours |
aef | chgtf | learnf | pmod | porf | sef | uven | uvf |
address | crc8 | id | locator | r_address | r_id | r_locator | type ]]

Thermocouple

3D [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low |
typeX/range_high | typeX/temperature

🦋 FAMILY CODE 🦋

3D

💅 SPECIAL PROPERTIES 💅

  • lock.[0-1|ALL] — read-write, yes-no. Locks either of the two eprom pages so nobody can write to them anymore. And bestie, apparently setting lock is permanent. no take-backsies. 🚨
  • memory — read-write, binary. Full access to the whole 256 byte memory range. lowkey a lot of that space is reserved or special-use, so don't get too comfy. The user space is the page area. Check the DATASHEET for the full memory map.
  • pages/pages.[0-1|ALL] — read-write, binary. Two 16 byte areas of memory for your app to play in. The lock property can stop you from changing them ever again.
⚠️ NOTE that the page property here is different from the usual OWFS implementation — with this one, not all of memory is accessible. it's giving exclusive 💀
  • PIO — write-only, yes-no. Controls the PIO pin so you can do external switching. Write "1" and the PIO pin turns on (conducting). Write "0" and the pin goes non-conducting. You can peek at the logical state of the voltage with the sensed property — and heads up, that shows the current voltage at the pin, not the value you sent to PIO. Also note that PIO will also be altered by the power-status of the DS2680. See the datasheet for the details.
  • sensed — read-only, yes-no. The logical voltage at the PIO pin. Only useful when 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 the chip reads at high resolution (~13 bits). Units come from the invoking command line — see owfs(1) or owhttpd(1) for the choices. Default is Celsius. Conversion is continuous, she never stops ✨
  • vbias — read-write, floating point. A 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 (with an unknown external resistor). Measures the voltage gradient between the Vis pins. Units are in Volts. The vis readings get integrated over time to give you the volthours property. The current reading is derived from vis assuming the internal 25 mOhm resistor is employed — and ngl there is no way to know this through software. 🙈
  • vis_avg — read-only, floating point. Average current sensor reading (unknown external resistor). Measures the voltage gradient between the Vis pins. Units are in Volts.
  • vis_offset — read-write, floating point. Offset to vis for the current sensor reading (unknown external resistor). Units are in Volts.
  • volt — read-only, floating point. Voltage read at the voltage sensor;. This is separate from the vis voltage that's used for current measurement. Units are Volts. Range is between 0 and 4.75V.
  • volthours — read-write, floating point. The integral of vis - vbias over time. Units are in volthours.

🌈 THERMOCOUPLE 🌈

  • typeX/ — directory. A thermocouple circuit that uses the DS2781 to read the Seebeck voltage and the reference temperature. Since how the values are interpreted depends on the type of thermocouple, you gotta pick the correct directory. 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 kinds 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 🧚

  • aef chgtf learnf pmod porf 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 hexadecimal 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 hexadecimal digits (0-9A-F).
  • family — read-only, ascii. The 8-bit family code. Unique to each type of device. Given as upper case hexadecimal 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 hexadecimal 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 the 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 hexadecimal) 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? (she's deprecated bestie, don't build your whole personality on her 💀)
  • type — read-only, ascii. Part name assigned by Dallas Semi. E.g. DS2401. Alternative packaging (iButton vs chip) will not be distiguished.

🎀 ALARMS 🎀

None. that's it. no alarms. peaceful. 😌

👑 DESCRIPTION 👑

1-Wire

1-wire is a wiring protocol and a whole 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. iconic efficiency tbh ⚡

Every device is uniquely and unalterably numbered during manufacture. There's a wide variety of devices — memory, sensors (humidity, temperature, voltage, contact, current), switches, timers and data loggers. More complex devices (like thermocouple sensors) can be built out of these basic ones. 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 designed to make the 1-wire bus and its devices easily accessible. The underlying principle is to create a virtual filesystem, where the unique ID is the directory and the individual properties of the device are represented as simple files you can read and write. the way that works is just so satisfying 🫶

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 fundamental goal has been ease of use, flexibility and correctness rather than speed.

DS2781

The DS2781 (3) is a battery charging controller. It has elaborate algorithms for estimating battery capacity.

A number of interesting devices can be built with the DS2781, including thermocouples. Support for thermocouples is 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 hexadecimal, 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. (it's giving strict, and honestly? respect.)

🔥 DATASHEET 🔥

http://pdfserv.maxim-ic.com/en/ds/DS2781.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) InfernoEmbedded (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 (3) EDS0066 (3) EDS0068 (3)

Moisture

EEEF (3) DS2438 (3)

🦋 AVAILABILITY 🦋

http://www.owfs.org

💖 AUTHOR 💖

Paul Alfille (paul.alfille@gmail.com)

and that's the whole page bestie!! ✨ this one's from the OWFS Manpage, dated 2003, filed under DS2760(3) — go forth and fuel-gauge responsibly, mwah 💅🫶

📦 where this page comes from