W1_THERM_DS28EA00 0x42
==================== ====
-Support is provided through the sysfs w1_slave file. Each open and
-read sequence will initiate a temperature conversion then provide two
+Support is provided through the sysfs entry ``w1_slave``. Each open and
+read sequence will initiate a temperature conversion, then provide two
lines of ASCII output. The first line contains the nine hex bytes
read along with a calculated crc value and YES or NO if it matched.
If the crc matched the returned values are retained. The second line
displays the retained values along with a temperature in millidegrees
Centigrade after t=.
-Alternatively, temperature can be read using temperature sysfs, it
-return only temperature in millidegrees Centigrade.
+Alternatively, temperature can be read using ``temperature`` sysfs, it
+returns only the temperature in millidegrees Centigrade.
-A bulk read of all devices on the bus could be done writing 'trigger'
-in the therm_bulk_read sysfs entry at w1_bus_master level. This will
-sent the convert command on all devices on the bus, and if parasite
-powered devices are detected on the bus (and strong pullup is enable
+A bulk read of all devices on the bus could be done writing ``trigger``
+to ``therm_bulk_read`` entry at w1_bus_master level. This will
+send the convert command to all devices on the bus, and if parasite
+powered devices are detected on the bus (and strong pullup is enabled
in the module), it will drive the line high during the longer conversion
time required by parasited powered device on the line. Reading
-therm_bulk_read will return 0 if no bulk conversion pending,
+``therm_bulk_read`` will return 0 if no bulk conversion pending,
-1 if at least one sensor still in conversion, 1 if conversion is complete
but at least one sensor value has not been read yet. Result temperature is
-then accessed by reading the temperature sysfs entry of each device, which
+then accessed by reading the ``temperature`` entry of each device, which
may return empty if conversion is still in progress. Note that if a bulk
read is sent but one sensor is not read immediately, the next access to
-temperature on this device will return the temperature measured at the
+``temperature`` on this device will return the temperature measured at the
time of issue of the bulk read command (not the current temperature).
A strong pullup will be applied during the conversion if required.
-``conv_time`` sysfs entry is used to get current conversion time (read), and
+``conv_time`` is used to get current conversion time (read), and
adjust it (write). A temperature conversion time depends on the device type and
it's current resolution. Default conversion time is set by the driver according
to the device datasheet. A conversion time for many original device clones
deviate from datasheet specs. There are three options: 1) manually set the
correct conversion time by writing a value in milliseconds to ``conv_time``; 2)
auto measure and set a conversion time by writing ``1`` to
-``conv_time``; 3) use ``features`` entry to enable poll for conversion
+``conv_time``; 3) use ``features`` to enable poll for conversion
completion. Options 2, 3 can't be used in parasite power mode. To get back to
the default conversion time write ``0`` to ``conv_time``.
-Writing a value between 9 and 12 to the sysfs w1_slave file will change the
-precision of the sensor for the next readings. This value is in (volatile)
-SRAM, so it is reset when the sensor gets power-cycled.
+Writing a resolution value (in bits) to ``w1_slave`` will change the
+precision of the sensor for the next readings. Allowed resolutions are defined by
+the sensor. Resolution is reset when the sensor gets power-cycled.
-To store the current precision configuration into EEPROM, the value 0
-has to be written to the sysfs w1_slave file. Since the EEPROM has a limited
-amount of writes (>50k), this command should be used wisely.
+To store the current resolution in EEPROM, write ``0`` to ``w1_slave``.
+Since the EEPROM has a limited amount of writes (>50k), this command should be
+used wisely.
-Alternatively, resolution can be set or read (value from 9 to 12) using the
-dedicated resolution sysfs entry on each device. This sysfs entry is not present
-for devices not supporting this feature.
+Alternatively, resolution can be read or written using the dedicated
+``resolution`` entry on each device, if supported by the sensor.
-Some non-genuine DS18B20 chips are
-fixed in 12-bit mode only, so the actual resolution is read back from the chip
-and verified by the driver.
+Some non-genuine DS18B20 chips are fixed in 12-bit mode only, so the actual
+resolution is read back from the chip and verified.
Note: Changing the resolution reverts the conversion time to default.
-The write-only sysfs entry eeprom is an alternative for EEPROM operations:
- * 'save': will save device RAM to EEPROM
- * 'restore': will restore EEPROM data in device RAM.
+The write-only sysfs entry ``eeprom`` is an alternative for EEPROM operations.
+Write ``save`` to save device RAM to EEPROM. Write ``restore`` to restore EEPROM
+data in device RAM.
-ext_power syfs entry allow tho check the power status of each device.
- * '0': device parasite powered
- * '1': device externally powered
+``ext_power`` entry allows checking the power state of each device. Reads
+``0`` if the device is parasite powered, ``1`` if the device is externally powered.
-sysfs alarms allow read or write TH and TL (Temperature High an Low) alarms.
+Sysfs ``alarms`` allow read or write TH and TL (Temperature High an Low) alarms.
Values shall be space separated and in the device range (typical -55 degC
to 125 degC). Values are integer as they are store in a 8bit register in
-the device. Lowest value is automatically put to TL.Once set, alarms could
+the device. Lowest value is automatically put to TL. Once set, alarms could
be search at master level.
The module parameter strong_pullup can be set to 0 to disable the
detection algorithm. This feature allows you to determine the physical
location of the chip in the 1-wire bus without needing pre-existing
knowledge of the bus ordering. Support is provided through the sysfs
-w1_seq file. The file will contain a single line with an integer value
+``w1_seq``. The file will contain a single line with an integer value
representing the device index in the bus starting at 0.
``features`` sysfs entry controls optional driver settings per device.
-Insufficient power in parasite mode, line noise and insufficient conversion time
-may lead to conversion failure. Original DS18B20 and some clones allow for
+Insufficient power in parasite mode, line noise and insufficient conversion
+time may lead to conversion failure. Original DS18B20 and some clones allow for
detection of invalid conversion. Write bit mask ``1`` to ``features`` to enable
checking the conversion success. If byte 6 of scratchpad memory is 0xC after
conversion and temperature reads 85.00 (powerup value) or 127.94 (insufficient
power), the driver returns a conversion error. Bit mask ``2`` enables poll for
conversion completion (normal power only) by generating read cycles on the bus
after conversion starts. In parasite power mode this feature is not available.
-Feature bit masks may be combined (OR). See accompanying sysfs documentation:
-:ref:`Documentation/w1/slaves/w1_therm.rst <w1_therm>`
+Feature bit masks may be combined (OR). More details in
+Documentation/ABI/testing/sysfs-driver-w1_therm
GX20MH01 device shares family number 0x28 with DS18*20. The device is generally
-compatible with DS18B20. Added are lowest 2^-5, 2^-6 temperature bits in Config
-register; R2 bit in Config register enabling 13 and 14 bit resolutions. The
-device is powered up in 14-bit resolution mode. The conversion times specified
-in the datasheet are too low and have to be increased. The device supports
-driver features ``1`` and ``2``.
+compatible with DS18B20. Added are lowest 2\ :sup:`-5`, 2\ :sup:`-6` temperature
+bits in Config register; R2 bit in Config register enabling 13 and 14 bit
+resolutions. The device is powered up in 14-bit resolution mode. The conversion
+times specified in the datasheet are too low and have to be increased. The
+device supports driver features ``1`` and ``2``.
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