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doc/reference.xml: Added CR_PACK_FLAGS()

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Added description of CR_PACK_FLAGS() macro and the various flag bits.
This commit is contained in:
Ian Abbott 2012-05-09 17:12:23 +01:00
parent c3ba569f87
commit b41732fa62
1 changed files with 74 additions and 0 deletions
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doc/reference.xml
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@ -108,6 +108,80 @@ not supported, they are silently ignored.
</para>
</section>
<section id="ref-macro-CR-PACK-FLAGS">
<title>
CR_PACK_FLAGS
</title>
<para>
<function>CR_PACK_FLAGS<parameter>chan</parameter><parameter>range</parameter>
<parameter>aref</parameter><parameter>flags</parameter></function>
is similar to
<function><link linkend="ref-macro-CR-PACK">CR_PACK</link></function>
but can be used to combine one or more flag bits (bitwise-ORed together in
the <parameter class="function">flags</parameter> parameter) with the other
parameters.
<programlisting>
<![CDATA[
#define CR_PACK_FLAGS(chan, range, aref, flags) \
(CR_PACK(chan, range, aref) | ((flags) & CR_FLAGS_MASK))
]]>
</programlisting>
Depending on context, the
<parameter class="function">chan</parameter> parameter might not be a channel;
it could be a trigger source, clock source, gate source etc. (in which case,
the <parameter class="function">range</parameter> and
<parameter class="function">aref</parameter> parameters would probably be set
to <literal>0</literal>), and the flags would modify the source in some
device-dependant way.
</para>
<para>
The following flag values are defined:
<variablelist>
<varlistentry>
<term><constant>CR_ALT_FILTER</constant><anchor id="cr-alt-filter"/></term>
<term><constant>CR_DITHER</constant></term>
<term><constant>CR_DEGLITCH</constant></term>
<listitem>
<para>
(all the same) specify that some sort of filtering is to be done
on the channel, trigger source, etc.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>CR_ALT_SOURCE</constant><anchor id="cr-alt-source"/></term>
<listitem>
<para>
specifies that some alternate source is to be used for the channel
(usually a calibration source).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>CR_EDGE</constant><anchor id="cr-edge"/></term>
<listitem>
<para>
is usually combined with a trigger source number to specify that the
trigger source is edge-triggered if the hardware and driver supports
both edge-triggering and level-triggering. If both are supported,
not asserting this flag specifies level-triggering.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>CR_INVERT</constant><anchor id="cr-invert"/></term>
<listitem>
<para>
specifies that the trigger source, gate source, etc. is to be inverted.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</section>
<section id="ref-macro-RANGE-LENGTH">
<title>
RANGE_LENGTH (deprecated)