sht3xtemp(4) - NetBSD Manual Pages

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SHT3XTEMP(4)            NetBSD Kernel Interfaces Manual           SHT3XTEMP(4)

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 opera- tion, repeatability, heater controls, periodic update rate and crc valid- ity 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 measure- ment. 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 mea- surement 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.
envsys(4), iic(4), envstat(8), sysctl(8)
The sht3xtemp driver first appeared in NetBSD 10.0.
The sht3xtemp driver was written by Brad Spencer <>.
The datasheet did not provide enough information to get the alarm func- tion of the chip working. NetBSD 10.0 October 31, 2021 NetBSD 10.0
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