sht3xtemp
—
Driver for Sensirion SHT30/SHT31/SHT35 sensor chip via I2C
bus
sht3xtemp* at iic? addr 0x44
sht3xtemp* at iic? addr 0x45
The sht3xtemp
driver provides measurements from the
SHT30/SHT31/SHT35 humidity/temperature sensors via the
envsys(4) framework. The
sht3xtemp
addr argument selects
the address at the iic(4) bus. The
mode of operation, repeatability, heater controls, periodic update rate and
crc validity can be changed through
sysctl(8) nodes.
The following sysctl(3) variables
are provided:
hw.sht3xtemp0.modes
- Lists the modes supported by the driver and chip.
hw.sht3xtemp0.mode
- Set the operation mode of the chip. The SHT3X chip can run in a
single-shot measurement mode or a periodic update mode. Use one of the
strings listed in
hw.sht3xtemp.modes
.
hw.sht3xtemp0.rates
- List the periodic update rates supported by the driver and chip.
hw.sht3xtemp0.rate
- Set the periodic update rate when the mode of operation is set to
periodic. The unit for this is measurements per second, or ART which is a
mode that operates at an update rate of 4Hz higher response time. Use one
of the strings listed in
hw.sht3xtemp.rates
.
Since it is possible to have subsecond periodic updates from
the chip if so desired a device file is provided that can be used to get
the raw temperature and humidity values outside of the
envsys(4) framework. The
structure of this output is the raw temperature plus an 8-bit CRC
followed by the raw humidity plus an 8-bit CRC.
hw.sht3xtemp0.repeatabilities
- List the valid values for the repeatability used for a measurement.
hw.sht3xtemp0.repeatability
- Set the repeatability for the measurement. The higher the repeatability
the longer the measurement will take and the more power used. Use one of
the strings listed in
hw.sht3xtemp.repeatabilities
.
hw.sht3xtemp0.ignorecrc
- If set, the crc calculation for %RH and temperature in the measurement
phrase will be ignored.
hw.sht3xtemp0.heateron
- Turn the heater on and off.
hw.sht3xtemp0.debug
- If the driver is compiled with
SHT3X_DEBUG
, this
node will appear and can be used to set the debugging level.
hw.sht3xtemp0.readattempts
- To read %RH or temperature the chip requires that the command be sent,
then a delay must be observed before a read can be done to get the values
back. The delays are documented in the datasheet for the chip. The driver
will attempt to read back the values readattempts number of times. The
default is 10 which should be more than enough for most purposes.
- /dev/sht3xtempu
- SHT3X device unit u file.
The sht3xtemp
driver first appeared in
NetBSD 10.0.
The datasheet did not provide enough information to get the alarm function of
the chip working.