69 lines · plain
1Kernel driver sht212===================3 4Supported chips:5 6 * Sensirion SHT217 8 Prefix: 'sht21'9 10 Addresses scanned: none11 12 Datasheet: Publicly available at the Sensirion website13 14 https://www.sensirion.com/file/datasheet_sht2115 16 17 18 * Sensirion SHT2519 20 Prefix: 'sht25'21 22 Addresses scanned: none23 24 Datasheet: Publicly available at the Sensirion website25 26 https://www.sensirion.com/file/datasheet_sht2527 28 29 30Author:31 32 Urs Fleisch <urs.fleisch@sensirion.com>33 34Description35-----------36 37The SHT21 and SHT25 are humidity and temperature sensors in a DFN package of38only 3 x 3 mm footprint and 1.1 mm height. The difference between the two39devices is the higher level of precision of the SHT25 (1.8% relative humidity,400.2 degree Celsius) compared with the SHT21 (2.0% relative humidity,410.3 degree Celsius).42 43The devices communicate with the I2C protocol. All sensors are set to the same44I2C address 0x40, so an entry with I2C_BOARD_INFO("sht21", 0x40) can be used45in the board setup code.46 47sysfs-Interface48---------------49 50temp1_input51 - temperature input52 53humidity1_input54 - humidity input55eic56 - Electronic Identification Code57 58Notes59-----60 61The driver uses the default resolution settings of 12 bit for humidity and 1462bit for temperature, which results in typical measurement times of 22 ms for63humidity and 66 ms for temperature. To keep self heating below 0.1 degree64Celsius, the device should not be active for more than 10% of the time,65e.g. maximum two measurements per second at the given resolution.66 67Different resolutions, the on-chip heater, and using the CRC checksum68are not supported yet.69