DS2437(3)

🎀 NAME 🎀

DS2437 — Smart Battery Monitor 💖

Okay bestie, this is a page from the One-Wire File System manual, section 3, and it's all about the DS2437 chip. She's a battery monitor. She's old. She's still kind of iconic. Let's get into it. 🦋

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✨ SYNOPSIS ✨

Temperature, Voltages and Memory. (Yes that's the entire synopsis. She's concise. We respect that. 👑)

1E [.]XXXXXXXXXXXX[XX][/[ current | date | disconnect/date |
disconnect/udate | endcharge/date | endcharge/udate | Ienable |
pages/page.[0-7|ALL] | temperature | udate | VAD | VDD | address | crc8
| id | locator | r_address | r_id | r_locator | type ]]

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🦋 FAMILY CODE 🦋

1E

That's it. That's the whole family code section. Slay. 💅

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🌸 SPECIAL PROPERTIES 🌸

🎀 date

read-write, ascii

A 26 character date representation of the counter value. Increments once per second, like a little heartbeat. 💓

Setting date to a null string will put the current system time.

Accepted date formats are:

Sat[urday] March 12 12:23:59 2001
Apr[il] 4 9:34:56 2002
3/23/04 23:34:57
current locale setting (your system's format)

🎀 current

read-only, integer

The current reading. Actual current depends on the Rsens resistor (see datasheet, bestie, the datasheet is right there).

The formula for current is I = current /(4096*Rsens) with units in Amps and Ohms.

Current measurement will be temporarily enabled (see Ienable) if not currently enabled (pun intended) for this reading. 😌

🎀 disconnect/date

read-write, ascii

A 26 character date representation of the disconnect/udate value. This is the time when the battery pack was removed from the charger. Format is the same as the date property.

🎀 disconnect/udate

read-write, unsigned integer

Representation of disconnect/date as a number. See udate for details.

🎀 endcharge/date

read-write, ascii

A 26 character date representation of the endcharge/udate value. Format is the same as the date property.

🎀 endcharge/udate

read-write, unsigned integer

Representation of endcharge/date as a number. See udate for details.

🎀 Ienable

read-write, unsigned integer

Status of current monitoring. When enabled, current sensing is performed 36.41 times/second. She's fast. ⚡

Values of Ienable are:

• 0 — no current conversion
• 1 — current conversion enabled
• 2 — current conversion and accumulation
• 3 — current conversion and accumulation with EEPROM backup

🎀 pages/page.0 ... pages/page.7, pages/page.ALL

read-write, binary

Memory is split into 8 pages of 8 bytes each. Only the pages 3-7 are really available, and some of that appears to be reserved. See the datasheet for details.

ALL is an aggregate of the pages. Each page is accessed sequentially.

🎀 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 takes ~20 msec.

🎀 udate

read-write, unsigned integer

Time represented as a number. udate increments once per second.

Usually set to unix time standard: number of seconds since Jan 1, 1970. The date field will be the unix representation (ascii text) of udate and setting either will change the other. They're linked, fr fr. 🔗

🎀 VAD VDD

read-only, floating point

Voltage read (~10 bits) at the one of the chip's two supply voltages. Range VDD= 2.4V to 10V, VAD=1.5 to 10V.

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💜 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 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?

⚠️ Heads up bestie: this one is DEPRECATED. She's giving legacy energy. Still documented, still readable, but like… you've been warned. 💀

🫶 type

read-only, ascii

Part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging (iButton vs chip) will not be distinguished.

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🚨 ALARMS 🚨

None.

Not one. Zero. No alarms here. The vibe is 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. Power over the data line?? She's doing the most and honestly, we love her for it. 🔥

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. Main character = the master, periodt.

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. It's giving "everything is a file" and honestly? Iconic.

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. Correctness over clout. 💅

🌟 DS2437

The DS2437 (3) is an obsolete version of the DS2438 (3) battery chip. Current sensing is available, but not implemented. The major advantage compared to the DS2436 is that two voltages can be read, allowing correcting circuit measurements to supply voltage and temperature. A better comparison is the DS276x family of chips.

🫶 Real talk: she's obsolete, and the current sensing is available but not implemented. No cap.

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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/DS2437.pdf

http://pdfserv.maxim-ic.com/en/an/humsensor.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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Okay that's the whole page bestie, you ate that 💅✨

This was the OWFS Manpage, dated 2003, for DS2437(3). Go read the datasheet, stay hydrated, and remember: current sensing is available but not implemented, and neither is texting back. 🦋🎀💖