Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Kernel driver sht3x 2 =================== 3 4 Supported chips: 5 * Sensirion SHT3x-DIS 6 Prefix: 'sht3x' 7 Addresses scanned: none 8 Datasheet: http://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/Humidity/Sensirion_Humidity_Datasheet_SHT3x_DIS.pdf 9 10 Author: 11 David Frey <david.frey@sensirion.com> 12 Pascal Sachs <pascal.sachs@sensirion.com> 13 14 Description 15 ----------- 16 17 This driver implements support for the Sensirion SHT3x-DIS chip, a humidity 18 and temperature sensor. Temperature is measured in degrees celsius, relative 19 humidity is expressed as a percentage. In the sysfs interface, all values are 20 scaled by 1000, i.e. the value for 31.5 degrees celsius is 31500. 21 22 The device communicates with the I2C protocol. Sensors can have the I2C 23 addresses 0x44 or 0x45, depending on the wiring. See 24 Documentation/i2c/instantiating-devices for methods to instantiate the device. 25 26 There are two options configurable by means of sht3x_platform_data: 27 1. blocking (pull the I2C clock line down while performing the measurement) or 28 non-blocking mode. Blocking mode will guarantee the fastest result but 29 the I2C bus will be busy during that time. By default, non-blocking mode 30 is used. Make sure clock-stretching works properly on your device if you 31 want to use blocking mode. 32 2. high or low accuracy. High accuracy is used by default and using it is 33 strongly recommended. 34 35 The sht3x sensor supports a single shot mode as well as 5 periodic measure 36 modes, which can be controlled with the update_interval sysfs interface. 37 The allowed update_interval in milliseconds are as follows: 38 * 0 single shot mode 39 * 2000 0.5 Hz periodic measurement 40 * 1000 1 Hz periodic measurement 41 * 500 2 Hz periodic measurement 42 * 250 4 Hz periodic measurement 43 * 100 10 Hz periodic measurement 44 45 In the periodic measure mode, the sensor automatically triggers a measurement 46 with the configured update interval on the chip. When a temperature or humidity 47 reading exceeds the configured limits, the alert attribute is set to 1 and 48 the alert pin on the sensor is set to high. 49 When the temperature and humidity readings move back between the hysteresis 50 values, the alert bit is set to 0 and the alert pin on the sensor is set to 51 low. 52 53 sysfs-Interface 54 --------------- 55 56 temp1_input: temperature input 57 humidity1_input: humidity input 58 temp1_max: temperature max value 59 temp1_max_hyst: temperature hysteresis value for max limit 60 humidity1_max: humidity max value 61 humidity1_max_hyst: humidity hysteresis value for max limit 62 temp1_min: temperature min value 63 temp1_min_hyst: temperature hysteresis value for min limit 64 humidity1_min: humidity min value 65 humidity1_min_hyst: humidity hysteresis value for min limit 66 temp1_alarm: alarm flag is set to 1 if the temperature is outside the 67 configured limits. Alarm only works in periodic measure mode 68 humidity1_alarm: alarm flag is set to 1 if the humidity is outside the 69 configured limits. Alarm only works in periodic measure mode 70 heater_enable: heater enable, heating element removes excess humidity from 71 sensor 72 0: turned off 73 1: turned on 74 update_interval: update interval, 0 for single shot, interval in msec 75 for periodic measurement. If the interval is not supported 76 by the sensor, the next faster interval is chosen