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- Kernel driver htu21
- ===================
- Supported chips:
- * Measurement Specialties HTU21D
- Prefix: 'htu21'
- Addresses scanned: none
- Datasheet: Publicly available at the Measurement Specialties website
- http://www.meas-spec.com/downloads/HTU21D.pdf
- Author:
- William Markezana <william.markezana@meas-spec.com>
- Description
- -----------
- The HTU21D is a humidity and temperature sensor in a DFN package of
- only 3 x 3 mm footprint and 0.9 mm height.
- The devices communicate with the I2C protocol. All sensors are set to the
- same I2C address 0x40, so an entry with I2C_BOARD_INFO("htu21", 0x40) can
- be used in the board setup code.
- This driver does not auto-detect devices. You will have to instantiate the
- devices explicitly. Please see Documentation/i2c/instantiating-devices
- for details.
- sysfs-Interface
- ---------------
- temp1_input - temperature input
- humidity1_input - humidity input
- Notes
- -----
- The driver uses the default resolution settings of 12 bit for humidity and 14
- bit for temperature, which results in typical measurement times of 11 ms for
- humidity and 44 ms for temperature. To keep self heating below 0.1 degree
- Celsius, the device should not be active for more than 10% of the time. For
- this reason, the driver performs no more than two measurements per second and
- reports cached information if polled more frequently.
- Different resolutions, the on-chip heater, using the CRC checksum and reading
- the serial number are not supported yet.
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