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AM2315TEMP(4)                Device Drivers Manual               AM2315TEMP(4)

NAME
     am2315temp - Driver for Aosong AM2315 sensor chip via I2C bus

SYNOPSIS
     am2315temp* at iic? addr 0x5c

DESCRIPTION
     The am2315temp driver provides measurements from the AM2315
     humidity/temperature sensors via the envsys(4) framework.  The am2315temp
     addr argument selects the address at the iic(4) bus.  The AM2315 has
     limits on how often the measurements can be read.  Adjustments to the
     number of times to take reading before considering it valid, and the
     number of ticks to wait between readings can be changed through sysctl(8)
     nodes.

     There are other oddities about the AM2315 that should be mentioned.  The
     datasheet says that the device should read no more often then every 2
     seconds, further, it also implies that a measurement is not performed
     until the device is 1) awake 2) has been asked for a measurement.  From
     observation, it has been noted that it is possible to ask for
     measurements more often than every 2 seconds, and actually get something
     that looks to be valid.  It may, in fact, be valid, but it has also been
     noted that the measurements do not appear to change.  This implies that a
     measurement was done, and then returned time and time again.  It has also
     been noticed that if measurements are taken very close to every 2
     seconds, that sometimes the device will return a I2C error on a read.  If
     this happens a lot, increase hw.am2315temp0.readticks a bit.

SYSCTL VARIABLES
     The following sysctl(3) variables are provided:

     hw.am2315temp0.readcount
             The number of times to take a reading before considering it
             valid.  This defaults to 2.

     hw.am2315temp0.readticks
             The number of ticks to wait in between readings.  The default is
             100.

     hw.am2315temp0.debug
             If the driver is compiled with AM2315_DEBUG, this node will
             appear and can be used to set the debugging level.

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

HISTORY
     The am2315temp driver first appeared in NetBSD 8.0.

AUTHORS
     The am2315temp driver was written by Brad Spencer
     <brad@anduin.eldar.org>.

BUGS
     The device does not appear to work with the gpioiic(4) bitbang
     controller.  When tried, reads would not error, but no data was returned.

NetBSD 8.99.34                 December 28, 2017                NetBSD 8.99.34