DS1825(3)

💖 NAME 💖

DS1825 — Programmable Resolution 1-Wire Digital Thermometer with ID, bestie 💅

MAX31826 — Digital Temperature Sensor with 1Kb Lockable EEPROM 🍓

MAX31850 MAX31851 — Cold-Junction Compensated Thermocouple 🌡️

Like, four whole icons in one manpage, and they all live on the same 1-wire bus. We love a versatile family. ✨

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✨ SYNOPSIS ✨

okay so this is the shape of everything you can poke at. Each one is a path on the 1-wire filesystem, and the family code 3B is the main character. 👑

Thermometer with hardware address pins (DS1825)

3B [.]XXXXXXXXXXXX[XX][/[ fasttemp | temperature | temperature9 |
temperature10 | temperature11 | temperature12 | latesttemp | power |
prog_addr | temphigh | templow | tempres | address | crc8 | id | locator |
r_address | r_id | r_locator | type ]]

Digital Temperature Sensor with 1Kb Lockable EEPROM (MAX31826)

3B [.]XXXXXXXXXXXX[XX][/[ temperature | latesttemp | power | memory |
pages/page.[0-15|ALL] | prog_addr | address | crc8 | id | locator |
r_address | r_id | r_locator | type ]]

Cold-Junction Compensated Thermocouple (MAX31850 and MAX31851)

3B [.]XXXXXXXXXXXX[XX][/[ temperature | latesttemp | thermocouple |
fault | open_circuit | ground_short | vdd_short | power | prog_addr |
address | crc8 | id | locator | r_address | r_id | r_locator | type ]]

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🌈 FAMILY CODE 🌈

3B

That's it. That's the whole section. Short king. 💜

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🎀 SPECIAL PROPERTIES 🎀

These are the properties that make these chips them. Extra, unique, no notes. 💅

power

• power — read-only, yes-no. Is the chip powered externally (=1) or parasitically from the data bus (=0)? iykyk ⚡

prog_addr

• prog_addr — read-only, 0-15. A distinguishing feature of the DS1825 (3) is the ability to set hardware pins for an address (0-15). This is an alternative to the unique 64-bit address that is set in the factory. So you can literally wire the address in. iconic 🔌

temperature

• temperature — read-only, floating point. Measured temperature with 12 bit resolution.

For the MAX31850 MAX31851 this is the cold-junction temperature — the temperature at the chip. See thermocouple. 🌡️

temperature9 temperature10 temperature11 temperature12

• temperature9, temperature10, temperature11, temperature12 — read-only, floating point (DS1825 only). Measured temperature at 9 to 12 bit resolution. There is a tradeoff of time versus accuracy in the temperature measurement. ⏱️✨

The MAX31826 MAX31850 MAX31851 measure all temperatures at 12 bit resolution and will return that resolution to all the possible temperature properties. no cap.

latesttemp

• latesttemp — read-only, floating point. Measured temperature at 9 to 12 bit resolution, depending on the resolution of the latest conversion on this chip. Reading this node will never trigger a temperature conversion. Intended for use in conjunction with /simultaneous/temperature. 🫶

fasttemp

• fasttemp — read-only, floating point. Equivalent to temperature9. literally the same vibe, just faster-named. 🏃♀️

thermocouple

• thermocouple — read-only, floating point (MAX31850 MAX31851 only). Measured temperature of the thermocouple at 16bit resolution. Cold-junction temperature compensated. 🔥

The actual thermocouple type used is set by the selected chip type, and is not discoverable in software. So don't come for the software, it simply does not know. 💀

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🦋 TEMPERATURE ALARM LIMITS 🦋

When the device exceeds either temphigh or templow temperature threshold, the device is in the alarm state, and will appear in the alarm directory. This provides an easy way to poll for temperatures that are unsafe, especially if simultaneous temperature conversion is done. safety first bestie. 🚨

Units for the temperature alarms are in the same temperature scale that was set for temperature measurements.

Temperature thresholds are stored in non-volatile memory and persist until changed, even if power is lost. glow-up that survives a power cut. 🔋✨

temphigh

• temphigh — read-write, integer. Shows or sets the lower limit for the high temperature alarm state.

templow

• templow — read-write, integer. Shows or sets the upper limit for the low temperature alarm state.

The MAX31826 does NOT have temperature thresholds and temperature alarm. not me getting left out of the alarm party 😭

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💜 TEMPERATURE RESOLUTION DEFAULT VALUE 💜

tempres

• tempres — read-write, integer. The device employs a non-volatile memory to store the default temperature resolution (9, 10, 11 or 12 bits) to be applied after power-up. This is useful if you use simultaneous temperature conversions. Reading this node gives you the value stored in the non-volatile memory. Writing sets a new power-on resolution value.

As a side effect, reading this node resets the temperature resolution used by simultaneous temperature conversions to its power-on value. It also affects the resolution value used by latesttemp, to scale the latest conversion value, so make sure to re-sample the temperature before accessing latesttemp after writing or reading the tempres value. ⚠️ like, re-read the temp first, fr fr.

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🍓 MEMORY 🍓

Only the MAX31826 supports memory functions. the rest of y'all sit this one out. 🙈

pages/page.0 .. pages/page.15, pages/page.ALL

• pages/page.0 .. pages/page.15, pages/page.ALL — read/write, binary. EEPROM memory pages of 8 bytes each. See the datasheet about locking contents. 🔒

memory

• memory — read/write, binary. EEPROM memory of 128 bytes. See the datasheet about locking contents. 🔒

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🧚 FAULT REPORTING 🧚

Only the MAX31850 MAX31851 supports fault reporting. everyone else, no drama for you today. 💅

fault

• fault — read-only, yes-no. Fault in last thermocouple conversion.

open_circuit

• open_circuit — read-only, yes-no. Thermocouple leads disconnected.

ground_short

• ground_short — read-only, yes-no. Thermocouple lead shorted to ground.

vdd_short

• vdd_short — read-only, yes-no. Thermocouple lead shorted to supply voltage.

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⭐ STANDARD PROPERTIES ⭐

The whole 1-wire fam shares these. Every chip has them, they're the blueprint, the foundation, the base layer. 🫶

address, r_address

• 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

• 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

• 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

• 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

• 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)

• present — read-only, yes-no. Is the device currently present on the 1-wire bus?

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

type

• 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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🌸 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, we love efficiency. ⚡

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. so many adapters, all valid. 🫶

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. filesystem but make it sensors. 📂✨

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 ate, periodt. 💅

DS1825

The DS1825 (3) is one of several available 1-wire temperature sensors. Alternatives are the DS18S20 (3), DS18B20 (3), and DS1822 (3) as well as temperature/voltage measurements in the DS2436 (3) and DS2438 (3). For truly versatile temperature measurements, see the protean DS1921 (3) Thermachron (3). 👑

The DS1825 (3) can select between 4 resolutions spanning the fastest/roughest and slowest/best. pick your fighter. 🥊

MAX31826

The MAX31826 shares a family code with the DS1825 but has differences in some of its functions.

The MAX31826 has 128 bytes of EEPROM memory (as 16 pages of 8 bytes) while the DS1825 has no memory available. 😭

The MAX31826 measures temperature at 12 bit resolution as fast as the DS1825's lowest resolution (and always uses 12-bit resolution). On the other hand it has no temperature thresholds or alarm function.

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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. MUST be correct, no pressure but it's giving pressure. ⚠️

Both the MAX31826 and the DS1825 allow hardware selection of part of the address, which can assist selecting between chips is some circuit designs. hardware addressing? so cool. 🎀

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💖 DATASHEET 💖

• DS1825 — http://pdfserv.maxim-ic.com/en/ds/DS1825.pdf
• MAX31826 — http://datasheets.maxim-ic.com/en/ds/MAX31826.pdf

go read the datasheets bestie, they're long but they're worth it. 📚✨

✨ SEE ALSO ✨

okay bestie, if you wanna go down the rabbit hole, here's literally everyone else in the DS1825 extended universe 💫 no gatekeeping, periodt. iykyk 💅

Programs

the main character apps:

• owfs (1)
• owhttpd (1)
• owftpd (1)
• owserver (1)
• owdir (1)
• owread (1)
• owwrite (1)
• owpresent (1)
• owtap (1)

Configuration and testing

config besties:

• owfs (5)
• owtap (1)
• owmon (1)

Language bindings

polyglot queens:

• owtcl (3)
• owperl (3)
• owcapi (3)

Clocks

time girlies:

• DS1427 (3)
• DS1904 (3)
• DS1994 (3)
• DS2404 (3)
• DS2404S (3)
• DS2415 (3)
• DS2417 (3)

ID

origin stories:

• DS2401 (3)
• DS2411 (3)
• DS1990A (3)

Memory

she remembers everything:

• 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

flip the vibe:

• DS2405 (3)
• DS2406 (3)
• DS2408 (3)
• DS2409 (3)
• DS2413 (3)
• DS28EA00 (3)
• InfernoEmbedded (3)

Temperature

the moment we've all been waiting for:

• 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

moisture check:

• DS1922 (3)
• DS2438 (3)
• EDS0065 (3)
• EDS0068 (3)

Voltage

electric:

• DS2450 (3)

Resistance

she's not easy:

• DS2890 (3)

Multifunction (current, voltage, temperature)

does it all:

• 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

1, 2, step:

• DS2423 (3)

LCD Screen

display queen:

• LCD (3)
• DS2408 (3)

Crypto

secretive:

• DS1977 (3)

Pressure

feeling the pressure:

• DS2406 (3)
• TAI8570 (3)
• EDS0066 (3)
• EDS0068 (3)

Moisture

hydrated:

• EEEF (3)
• DS2438 (3)

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✨ AVAILABILITY ✨

You can find the whole thing at http://www.owfs.org — go get her, bestie 💅

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✨ AUTHOR ✨

The author? Paul Alfille (paul.alfille@gmail.com) — iconic behavior, no cap 💖

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This page came from the OWFS Manpage, dated 2006, for DS1825(3) — bye bestie, ily! 💖✨