DS2720(3)

✨ NAME ✨

DS2720 — Efficient Addressable Single-cell Rechargeable Lithium Protection IC 💅

okay so quick context bestie: this page lives in the One-Wire File System manual, section 3, which is why it's called DS2720(3). It's about one specific lil chip and every property you can poke at on it. Let's go. 🦋

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🌸 SYNOPSIS 🌸

Memory and warnings. 🫶

31 [.]XXXXXXXXXXXX[XX][/[ lock.[0-1|ALL] | memory | pages/page.[0-1|ALL] |
cc | ce | dc | de | doc | ot | ov | psf | uv |
address | crc8 | id | locator | r_address | r_id | r_locator | type ]]

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💖 FAMILY CODE 💖

31

That's the whole section. The family code is 31. Iconic, minimal, ate. ✨

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🎀 SPECIAL PROPERTIES 🎀

🔒 lock.[0-1|ALL]

read-write, yes-no

Locks either one of the two eprom pages so nobody can write to it anymore. And apparently setting lock is permanent. Like, permanent permanent.

⚠️ bestie, hear me: apparently setting lock is permanent. No undo button. No take-backs. Do not vibe-check this one on a device you care about. 💀

🧠 memory

read-write, binary

This is your door into the full 256 byte memory range. A big chunk of that space is reserved or for special use — the user space is the page area. For the full memory map, go see the DATASHEET. 📜

📄 pages/pages.[0-1|ALL]

read-write, binary

Two 8 byte areas of memory for your user application. The lock property can stop any further alteration of them.

📌 NOTE: the page property here is different from the common OWFS implementation, in that all of memory is not accessible. Not all memory, bestie. Just the pages. 🙈

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🕵️ OBSCURE PROPERTIES 🕵️

⚡ cc ce dc de doc ot ov uv

varies, yes-no

These are bit flags that map to the various battery management functions of the chip. For the deets on the identically named entries, check the DATASHEET. General rule of thumb: writing "0" corresponds to a 0 bit value, and a non-zero write corresponds to a 1 bit value. 🧚

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👑 STANDARD PROPERTIES 👑

🪪 address, r_address

read-only, ascii

The entire 64-bit unique ID, served up 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 a cyclic redundancy check. It's 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. It does not include the family code or the 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

This one 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 your connection is behind a Link Locator, the locator will show a unique 8-byte number (16 character hexadecimal) starting with family code FE. If there's no Link Locator sitting 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?

⚠️ DEPRECATED, bestie. It's still here, it still answers, but it's giving legacy energy. 💀

🏷️ type

read-only, ascii

The part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging (iButton vs chip) will not be distiguished. 🎀

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🚨 ALARMS 🚨

None. Not a single one. The vibes are calm. 😌

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📖 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 principle 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 fundamental goal has been ease of use, flexibility and correctness rather than speed. 🐢💖

🔋 DS2720

The DS2720 (3) is a battery charging monitor. Besides it's intended use, it may have use in monitoring for device failures. 🩺

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🧭 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. ✅

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📄 DATASHEET 📄

http://pdfserv.maxim-ic.com/en/ds/DS2720.pdf

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👀 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)

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🌈 AVAILABILITY 🌈

http://www.owfs.org

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💌 AUTHOR 💌

Paul Alfille (paul.alfille@gmail.com)

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and that's the whole page, bestie!! 🫶 this was the OWFS Manpage, dated 2003, and you just read DS2720(3). go forth and monitor those batteries responsibly. no cap. 💅✨🎀