AHT20TEMP(4)

AHT20TEMP(4) | Device Drivers Manual | AHT20TEMP(4)

# NAME

`aht20temp` — Driver for Guangzhou Aosong AHT20 sensor chip via I2C bus

# SYNOPSIS

`aht20temp* at iic? addr 0x38`

# DESCRIPTION

The `aht20temp` driver provides measurements from the AHT20 humidity/temperature sensors via the envsys(4) framework. The `aht20temp` addr argument selects the address at the iic(4) bus. The crc validity can be changed through sysctl(8) nodes.

# SYSCTL VARIABLES

The following sysctl(3) variables are provided:

`hw.aht20temp0.ignorecrc`
  If set, the crc calculation for %RH and temperature will be ignored.
`hw.aht20temp0.debug`
  If the driver is compiled with `AHT20_DEBUG`, this node will appear and can be used to set the debugging level.
`hw.aht20temp0.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.

# SEE ALSO

envsys(4), iic(4), envstat(8), sysctl(8)

# HISTORY

The `aht20temp` driver first appeared in NetBSD 10.0.

# AUTHORS

The `aht20temp` driver was written by Brad Spencer <brad@anduin.eldar.org>.

November 15, 2022 | NetBSD 11.0