DS1825(3) One-Wire File System DS1825(3) # [NAME](#NAME) **DS1825** - Programmable Resolution 1-Wire Digital Thermometer with ID [**MAX31826**](#MAX31826) \- Digital Temperature Sensor with 1Kb Lockable EEPROM [**MAX31850 MAX31851**](#MAX31850) \- Cold-Junction Compensated Thermocouple # [SYNOPSIS](#SYNOPSIS) ## [Thermometer with hardware address pins (DS1825)](#Thermometer_with_hardware_address_pins_%28DS1825%29) **3B** \[.]XXXXXXXXXXXX\[XX][/[ See the file man3/temperatures\_mini.3so. | **latesttemp** | **power** | **prog\_addr** | **temphigh** | **templow** | **tempres** | See the file man3/standard\_mini.3so. ]] ## [Digital Temperature Sensor with 1Kb Lockable EEPROM (MAX31826)](#Digital_Temperature_Sensor_with_1Kb_Lockable_EEPROM_%28MAX31826%29) **3B** \[.]XXXXXXXXXXXX\[XX]\[/\[ **temperature** | **latesttemp** | **power** | **memory** | **pages/page.\[0-15|ALL]** | **prog\_addr** | See the file man3/standard\_mini.3so. ]] ## [Cold-Junction Compensated Thermocouple (MAX31850 and MAX31851)](#Cold-Junction_Compensated_Thermocouple_%28MAX31850_and_MAX31851%29) **3B** \[.]XXXXXXXXXXXX\[XX][/[ **temperature** | **latesttemp** | **thermocouple** | **fault** | **open\_circuit** | **ground\_short** | **vdd\_short** | **power** | **prog\_addr** | See the file man3/standard\_mini.3so. ]] # [FAMILY CODE](#FAMILY_CODE) *3B* # [SPECIAL PROPERTIES](#SPECIAL_PROPERTIES) ## [power](#power) *read-only,yes-no* Is the chip powered externally (=1) or from the parasitically from the data bus (=0)? ## [prog\_addr](#prog_addr) *read-only, 0-15* A distiguishing feature of the [**DS1825 (3)**](/man/os/owfs/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. ## [temperature](#temperature) *read-only, floating point* Measured temperature with 12 bit resolution. For the **MAX31850 MAX 31851** 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 resoltion and will return that resolution to all the possible temperature properties. ## [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* ## [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. See the file man3/temperature\_threshold.3so. The **MAX31826** does NOT have temperature thresholds and temperature alarm. See the file man3/temperature\_resolution.3so. # [MEMORY](#MEMORY) Only the **MAX31826** supports memory functions. ## [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. # [FAULT REPORTING](#FAULT_REPORTING) Only the **MAX31850 MAX31851** supports fault reporting. ## [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. # [STANDARD PROPERTIES](#STANDARD_PROPERTIES) See the file man3/standard.3so. # [DESCRIPTION](#DESCRIPTION) See the file man3/description.3so. ## [DS1825](#DS1825) The [**DS1825 (3)**](/man/os/owfs/DS1825.3) is one of several available 1-wire temperature sensors. Alternatives are the **[DS18S20 (3)](/man/os/owfs/DS18S20.3),** **DS18B20 (3),** and [**DS1822 (3)**](/man/os/owfs/DS1822.3) as well as temperature/voltage measurements in the [**DS2436 (3)**](/man/os/owfs/DS2436.3) and **[DS2438 (3)](/man/os/owfs/DS2438.3).** For truly versatile temperature measurements, see the protean **[DS1921 (3)](/man/os/owfs/DS1921.3) Thermachron (3).** The [**DS1825 (3)**](/man/os/owfs/DS1825.3) can select between 4 resolutionsspanning the fastest/roughest and slowest/best. ## [MAX31826](#MAX31826~2) The **MAX31826** shares a family code with the **DS1825** but has differences in some of its functions. The **MAX31826** has 128 btes 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. # [ADDRESSING](#ADDRESSING) See the file man3/addressing.3so. Both the **MAX31826** and the **DS1825** allow hardware selection of part of the address, which can assist selecting between chips is some circuit designs. # [DATASHEET](#DATASHEET) [**DS1825**](#DS1825~2) http://pdfserv.maxim-ic.com/en/ds/DS1825.pdf [**MAX31826**](#MAX31826~3) http://datasheets.maxim-ic.com/en/ds/MAX31826.pdf # [SEE ALSO](#SEE_ALSO) See the file man3/seealso.3so. # [AVAILABILITY](#AVAILABILITY) http://www.owfs.org # [AUTHOR](#AUTHOR) Paul Alfille (paul.alfille@gmail.com) 2006 OWFS Manpage --- Document: MAX31850(3) from owfs 3.2.4-r10 (Chainguard OS) Source: https://github.com/owfs/owfs