Loading...
1Kernel driver sht3x
2===================
3
4Supported chips:
5
6 * Sensirion SHT3x-DIS
7
8 Prefix: 'sht3x'
9
10 Addresses scanned: none
11
12 Datasheets:
13 - https://sensirion.com/media/documents/213E6A3B/63A5A569/Datasheet_SHT3x_DIS.pdf
14 - https://sensirion.com/media/documents/051DF50B/639C8101/Sensirion_Humidity_and_Temperature_Sensors_Datasheet_SHT33.pdf
15
16 * Sensirion STS3x-DIS
17
18 Prefix: 'sts3x'
19
20 Addresses scanned: none
21
22 Datasheets:
23 - https://sensirion.com/media/documents/1DA31AFD/61641F76/Sensirion_Temperature_Sensors_STS3x_Datasheet.pdf
24 - https://sensirion.com/media/documents/292A335C/65537BAF/Sensirion_Datasheet_STS32_STS33.pdf
25
26Author:
27
28 - David Frey <david.frey@sensirion.com>
29 - Pascal Sachs <pascal.sachs@sensirion.com>
30
31Description
32-----------
33
34This driver implements support for the Sensirion SHT3x-DIS and STS3x-DIS
35series of humidity and temperature sensors. Temperature is measured in degrees
36celsius, relative humidity is expressed as a percentage. In the sysfs interface,
37all values are scaled by 1000, i.e. the value for 31.5 degrees celsius is 31500.
38
39The device communicates with the I2C protocol. Sensors can have the I2C
40addresses 0x44 or 0x45 (0x4a or 0x4b for sts3x), depending on the wiring. See
41Documentation/i2c/instantiating-devices.rst for methods to instantiate the
42device.
43
44Even if sht3x sensor supports clock-stretch (blocking mode) and non-stretch
45(non-blocking mode) in single-shot mode, this driver only supports the latter.
46
47The sht3x sensor supports a single shot mode as well as 5 periodic measure
48modes, which can be controlled with the update_interval sysfs interface.
49The allowed update_interval in milliseconds are as follows:
50
51 ===== ======= ====================
52 0 single shot mode
53 2000 0.5 Hz periodic measurement
54 1000 1 Hz periodic measurement
55 500 2 Hz periodic measurement
56 250 4 Hz periodic measurement
57 100 10 Hz periodic measurement
58 ===== ======= ====================
59
60In the periodic measure mode, the sensor automatically triggers a measurement
61with the configured update interval on the chip. When a temperature or humidity
62reading exceeds the configured limits, the alert attribute is set to 1 and
63the alert pin on the sensor is set to high.
64When the temperature and humidity readings move back between the hysteresis
65values, the alert bit is set to 0 and the alert pin on the sensor is set to
66low.
67
68The serial number exposed to debugfs allows for unique identification of the
69sensors. For sts32, sts33 and sht33, the manufacturer provides calibration
70certificates through an API.
71
72sysfs-Interface
73---------------
74
75=================== ============================================================
76temp1_input: temperature input
77humidity1_input: humidity input
78temp1_max: temperature max value
79temp1_max_hyst: temperature hysteresis value for max limit
80humidity1_max: humidity max value
81humidity1_max_hyst: humidity hysteresis value for max limit
82temp1_min: temperature min value
83temp1_min_hyst: temperature hysteresis value for min limit
84humidity1_min: humidity min value
85humidity1_min_hyst: humidity hysteresis value for min limit
86temp1_alarm: alarm flag is set to 1 if the temperature is outside the
87 configured limits. Alarm only works in periodic measure mode
88humidity1_alarm: alarm flag is set to 1 if the humidity is outside the
89 configured limits. Alarm only works in periodic measure mode
90heater_enable: heater enable, heating element removes excess humidity from
91 sensor:
92
93 - 0: turned off
94 - 1: turned on
95update_interval: update interval, 0 for single shot, interval in msec
96 for periodic measurement. If the interval is not supported
97 by the sensor, the next faster interval is chosen
98repeatability: write or read repeatability, higher repeatability means
99 longer measurement duration, lower noise level and
100 larger energy consumption:
101
102 - 0: low repeatability
103 - 1: medium repeatability
104 - 2: high repeatability
105=================== ============================================================
106
107debugfs-Interface
108-----------------
109
110=================== ============================================================
111serial_number: unique serial number of the sensor in decimal
112=================== ============================================================
1Kernel driver sht3x
2===================
3
4Supported chips:
5
6 * Sensirion SHT3x-DIS
7
8 Prefix: 'sht3x'
9
10 Addresses scanned: none
11
12 Datasheet: https://www.sensirion.com/file/datasheet_sht3x_digital
13
14Author:
15
16 - David Frey <david.frey@sensirion.com>
17 - Pascal Sachs <pascal.sachs@sensirion.com>
18
19Description
20-----------
21
22This driver implements support for the Sensirion SHT3x-DIS chip, a humidity
23and temperature sensor. Temperature is measured in degrees celsius, relative
24humidity is expressed as a percentage. In the sysfs interface, all values are
25scaled by 1000, i.e. the value for 31.5 degrees celsius is 31500.
26
27The device communicates with the I2C protocol. Sensors can have the I2C
28addresses 0x44 or 0x45, depending on the wiring. See
29Documentation/i2c/instantiating-devices.rst for methods to instantiate the device.
30
31There are two options configurable by means of sht3x_platform_data:
32
331. blocking (pull the I2C clock line down while performing the measurement) or
34 non-blocking mode. Blocking mode will guarantee the fastest result but
35 the I2C bus will be busy during that time. By default, non-blocking mode
36 is used. Make sure clock-stretching works properly on your device if you
37 want to use blocking mode.
382. high or low accuracy. High accuracy is used by default and using it is
39 strongly recommended.
40
41The sht3x sensor supports a single shot mode as well as 5 periodic measure
42modes, which can be controlled with the update_interval sysfs interface.
43The allowed update_interval in milliseconds are as follows:
44
45 ===== ======= ====================
46 0 single shot mode
47 2000 0.5 Hz periodic measurement
48 1000 1 Hz periodic measurement
49 500 2 Hz periodic measurement
50 250 4 Hz periodic measurement
51 100 10 Hz periodic measurement
52 ===== ======= ====================
53
54In the periodic measure mode, the sensor automatically triggers a measurement
55with the configured update interval on the chip. When a temperature or humidity
56reading exceeds the configured limits, the alert attribute is set to 1 and
57the alert pin on the sensor is set to high.
58When the temperature and humidity readings move back between the hysteresis
59values, the alert bit is set to 0 and the alert pin on the sensor is set to
60low.
61
62sysfs-Interface
63---------------
64
65=================== ============================================================
66temp1_input: temperature input
67humidity1_input: humidity input
68temp1_max: temperature max value
69temp1_max_hyst: temperature hysteresis value for max limit
70humidity1_max: humidity max value
71humidity1_max_hyst: humidity hysteresis value for max limit
72temp1_min: temperature min value
73temp1_min_hyst: temperature hysteresis value for min limit
74humidity1_min: humidity min value
75humidity1_min_hyst: humidity hysteresis value for min limit
76temp1_alarm: alarm flag is set to 1 if the temperature is outside the
77 configured limits. Alarm only works in periodic measure mode
78humidity1_alarm: alarm flag is set to 1 if the humidity is outside the
79 configured limits. Alarm only works in periodic measure mode
80heater_enable: heater enable, heating element removes excess humidity from
81 sensor:
82
83 - 0: turned off
84 - 1: turned on
85update_interval: update interval, 0 for single shot, interval in msec
86 for periodic measurement. If the interval is not supported
87 by the sensor, the next faster interval is chosen
88=================== ============================================================