DragonFly On-Line Manual Pages

DS1825(3)                    One-Wire File System                    DS1825(3)

NAME
       DS1825 - Programmable Resolution 1-Wire Digital Thermometer with ID

       MAX31826
              - Digital Temperature Sensor with 1Kb Lockable EEPROM

       MAX31850 MAX31851
              - Cold-Junction Compensated Thermocouple

SYNOPSIS
   Thermometer with hardware address pins (DS1825)
       3B [.]XXXXXXXXXXXX[XX][/[

       See the file man3/temperatures_mini.3so.

       | power | prog_addr | temphigh | templow |

       See the file man3/standard_mini.3so.

       ]]

   Digital Temperature Sensor with 1Kb Lockable EEPROM (MAX31826)
       3B [.]XXXXXXXXXXXX[XX][/[ temperature | power | memory |
       pages/page.[0-15|ALL] | prog_addr |

       See the file man3/standard_mini.3so.

       ]]

   Cold-Junction Compensated Thermocouple (MAX31850 and MAX31851)
       3B [.]XXXXXXXXXXXX[XX][/[ temperature | thermocouple | fault |
       open_circuit | ground_short | vdd_short | power | prog_addr |

       See the file man3/standard_mini.3so.

       ]]

FAMILY CODE
       3B

SPECIAL PROPERTIES
   power
       read-only,yes-no
       Is the chip powered externally (=1) or from the parasitically from the
       data bus (=0)?

   prog_addr
       read-only, 0-15
       A distiguishing 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.

   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
       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.

   fasttemp
       read-only, floating point
       Equivalent to temperature9

   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.

MEMORY
       Only the MAX31826 supports memory functions.

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

FAULT REPORTING
       Only the MAX31850 MAX31851 supports fault reporting.

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

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

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

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

STANDARD PROPERTIES
       See the file man3/standard.3so.

DESCRIPTION
       See the file man3/description.3so.

   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 resolutionsspanning the
       fastest/roughest and slowest/best.

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

       MAX31826
              http://datasheets.maxim-ic.com/en/ds/MAX31826.pdf

SEE ALSO
       See the file man3/seealso.3so.

AVAILABILITY
       http://www.owfs.org

AUTHOR
       Paul Alfille (paul.alfille@gmail.com)

OWFS Manpage                         2006                            DS1825(3)