linux/Documentation/hwmon/sht21
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   1Kernel driver sht21
   2===================
   3
   4Supported chips:
   5  * Sensirion SHT21
   6    Prefix: 'sht21'
   7    Addresses scanned: none
   8    Datasheet: Publicly available at the Sensirion website
   9    http://www.sensirion.com/en/pdf/product_information/Datasheet-humidity-sensor-SHT21.pdf
  10
  11  * Sensirion SHT25
  12    Prefix: 'sht21'
  13    Addresses scanned: none
  14    Datasheet: Publicly available at the Sensirion website
  15    http://www.sensirion.com/en/pdf/product_information/Datasheet-humidity-sensor-SHT25.pdf
  16
  17Author:
  18  Urs Fleisch <urs.fleisch@sensirion.com>
  19
  20Description
  21-----------
  22
  23The SHT21 and SHT25 are humidity and temperature sensors in a DFN package of
  24only 3 x 3 mm footprint and 1.1 mm height. The difference between the two
  25devices is the higher level of precision of the SHT25 (1.8% relative humidity,
  260.2 degree Celsius) compared with the SHT21 (2.0% relative humidity,
  270.3 degree Celsius).
  28
  29The devices communicate with the I2C protocol. All sensors are set to the same
  30I2C address 0x40, so an entry with I2C_BOARD_INFO("sht21", 0x40) can be used
  31in the board setup code.
  32
  33sysfs-Interface
  34---------------
  35
  36temp1_input - temperature input
  37humidity1_input - humidity input
  38
  39Notes
  40-----
  41
  42The driver uses the default resolution settings of 12 bit for humidity and 14
  43bit for temperature, which results in typical measurement times of 22 ms for
  44humidity and 66 ms for temperature. To keep self heating below 0.1 degree
  45Celsius, the device should not be active for more than 10% of the time,
  46e.g. maximum two measurements per second at the given resolution.
  47
  48Different resolutions, the on-chip heater, using the CRC checksum and reading
  49the serial number are not supported yet.
  50
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