static/netbsd/man4/sht4xtemp.4 4.html


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<table class="head">
  <tr>
    <td class="head-ltitle">SHT4XTEMP(4)</td>
    <td class="head-vol">Device Drivers Manual</td>
    <td class="head-rtitle">SHT4XTEMP(4)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">sht4xtemp</code> &#x2014; <span class="Nd">Driver
    for Sensirion SHT40/SHT41/SHT45 sensor chip via I2C bus</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">sht4xtemp* at iic? addr 0x44</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">sht4xtemp</code> driver provides measurements
    from the SHT40/SHT41/SHT45 humidity/temperature sensors via the
    <a class="Xr">envsys(4)</a> framework. The <code class="Nm">sht4xtemp</code>
    <var class="Ar">addr</var> argument selects the address at the
    <a class="Xr">iic(4)</a> bus. The resolution, heater controls and crc
    validity can be changed through <a class="Xr">sysctl(8)</a> nodes.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYSCTL_VARIABLES"><a class="permalink" href="#SYSCTL_VARIABLES">SYSCTL
  VARIABLES</a></h1>
<p class="Pp">The following <a class="Xr">sysctl(3)</a> variables are
  provided:</p>
<dl class="Bl-tag">
  <dt id="hw.sht4xtemp0.resolutions"><a class="permalink" href="#hw.sht4xtemp0.resolutions"><code class="Li">hw.sht4xtemp0.resolutions</code></a></dt>
  <dd>Lists the resolutions supported by the driver and chip.</dd>
  <dt id="hw.sht4xtemp0.resolution"><a class="permalink" href="#hw.sht4xtemp0.resolution"><code class="Li">hw.sht4xtemp0.resolution</code></a></dt>
  <dd>Set the resolution, or number of bits, used for %RH and temperature. Use
      one of the strings listed in
      <code class="Li">hw.sht4xtemp.resolutions</code>.</dd>
  <dt id="hw.sht4xtemp0.ignorecrc"><a class="permalink" href="#hw.sht4xtemp0.ignorecrc"><code class="Li">hw.sht4xtemp0.ignorecrc</code></a></dt>
  <dd>If set, the crc calculation for %RH and temperature will be ignored.</dd>
  <dt id="hw.sht4xtemp0.heateron"><a class="permalink" href="#hw.sht4xtemp0.heateron"><code class="Li">hw.sht4xtemp0.heateron</code></a></dt>
  <dd>Turn the heater on and off. Please note that the heater is turned on right
      before the measurement and runs for a pulse width of time. Then the
      measurement is taken and the heater is turned off. There is no way to keep
      the heater running with this chip.</dd>
  <dt id="hw.sht4xtemp0.heaterstrength"><a class="permalink" href="#hw.sht4xtemp0.heaterstrength"><code class="Li">hw.sht4xtemp0.heaterstrength</code></a></dt>
  <dd>From 1 to 3, the amount of energy put into the heater. The higher the
      number, the more power used.</dd>
  <dt id="hw.sht4xtemp0.heaterpulses"><a class="permalink" href="#hw.sht4xtemp0.heaterpulses"><code class="Li">hw.sht4xtemp0.heaterpulses</code></a></dt>
  <dd>Lists the valid heater pulses supported by the driver and chip.</dd>
  <dt id="hw.sht4xtemp0.heaterpulse"><a class="permalink" href="#hw.sht4xtemp0.heaterpulse"><code class="Li">hw.sht4xtemp0.heaterpulse</code></a></dt>
  <dd>Set the heater pulse length. Use one of the strings listed in
      <code class="Li">hw.sht4xtemp.heaterpulses</code>.</dd>
  <dt id="hw.sht4xtemp0.debug"><a class="permalink" href="#hw.sht4xtemp0.debug"><code class="Li">hw.sht4xtemp0.debug</code></a></dt>
  <dd>If the driver is compiled with <code class="Dv">SHT4X_DEBUG</code>, this
      node will appear and can be used to set the debugging level.</dd>
  <dt id="hw.sht4xtemp0.readattempts"><a class="permalink" href="#hw.sht4xtemp0.readattempts"><code class="Li">hw.sht4xtemp0.readattempts</code></a></dt>
  <dd>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.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">envsys(4)</a>, <a class="Xr">iic(4)</a>,
    <a class="Xr">envstat(8)</a>, <a class="Xr">sysctl(8)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">sht4xtemp</code> driver first appeared in
    <span class="Ux">NetBSD 10.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <code class="Nm">sht4xtemp</code> driver was written by
    <span class="An">Brad Spencer</span>
    &lt;<a class="Mt" href="mailto:brad@anduin.eldar.org">brad@anduin.eldar.org</a>&gt;.</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">September 28, 2021</td>
    <td class="foot-os">NetBSD 10.1</td>
  </tr>
</table>