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Merge branch 'master' of ssh://comedi.org/git/comedi/comedilib

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Bernd Porr 2012-05-02 17:59:46 +01:00
commit 58e0e21ea9
3 changed files with 27 additions and 8 deletions
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9
doc/comedilib.xml
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@ -33,6 +33,11 @@
<surname>Porr</surname>
<email>Bernd.Porr@glasgow.ac.uk</email>
</author>
<author>
<firstname>Ian</firstname>
<surname>Abbott</surname>
<email>abbotti@mev.co.uk</email>
</author>
<copyright>
<year>1998-2003</year>
<holder>David Schleef</holder>
@ -49,6 +54,10 @@
<year>2012</year>
<holder>Bernd Porr</holder>
</copyright>
<copyright>
<year>2012</year>
<holder>Ian Abbott</holder>
</copyright>
<abstract>
<para>

24
doc/other.xml
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@ -108,27 +108,37 @@ Multiple channels can be read and written simultaneously using the
function
<funcsynopsis><funcprototype>
<funcdef>int <link linkend="func-ref-comedi-dio-bitfield"><function>comedi_dio_bitfield</function></link></funcdef>
<funcdef>int <link linkend="func-ref-comedi-dio-bitfield2"><function>comedi_dio_bitfield2</function></link></funcdef>
<paramdef><link linkend="ref-type-comedi-t">comedi_t</link> *<parameter>device</parameter></paramdef>
<paramdef>unsigned int <parameter>subdevice</parameter></paramdef>
<paramdef>unsigned int <parameter>write_mask</parameter></paramdef>
<paramdef>unsigned int *<parameter>bits</parameter></paramdef>
<paramdef>unsigned int <parameter>base_channel</parameter></paramdef>
</funcprototype></funcsynopsis>
Each channel is assigned to a bit in the
Each channel from <parameter class="function">base_channel</parameter>
to <parameter class="function">base_channel</parameter> &plus;
<literal>31</literal> is assigned to a bit in the
<parameter class="function">write_mask</parameter> and
<parameter class="function">bits</parameter>
bitfield. If a bit in
bitfield with bit 0 assigned to channel
<parameter class="function">base_channel</parameter>, bit 1 assigned to channel
<parameter class="function">base_channel</parameter> &plus;
<literal>1</literal>, etc. If a bit in
<parameter class="function">write_mask</parameter> is set, the
corresponding bit in <parameter class="function">*bits</parameter> will
be written to the corresponding digital output line.
be written to the digital output line corresponding to the channel given by
<parameter class="function">base_channel</parameter> plus the bit number.
Each digital line is then read and placed into
<parameter class="function">*bits</parameter>. The value
of bits in <parameter class="function">*bits</parameter> corresponding
to digital output lines is undefined and device-specific. Channel
<literal>0</literal> is the least significant bit in the bitfield;
channel <literal>31</literal> is the most significant bit. Channels
higher than <literal>31</literal> cannot be accessed using this method.
<parameter class="function">base_channel</parameter> &plus;
<literal>0</literal> is the least significant bit in the bitfield. No
more than 32 channels at once can be accessed using this method.
<emphasis role="strong">Warning!</emphasis> Older versions of &comedi;
may ignore <parameter class="function">base_channel</parameter> and treat
it as <literal>0</literal> unless the subdevice has more than 32 channels.
</para>
<para>

2
doc/tutorial.xml
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@ -212,7 +212,7 @@
</programlisting>
<para>
For advanced programmers the
function <link linkend="func-ref-comedi-comedi-get-buffer-contents"><function>comedi_get_buffer_contents</function></link>
function <link linkend="func-ref-comedi-get-buffer-contents"><function>comedi_get_buffer_contents</function></link>
is useful to check if there is actually data in the ringbuffer
so that a call of <function>read</function> can be avoided for example
when the data readout is called by a timer call-back function.