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>comedi_data_read</H1
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>Name</H2
>comedi_data_read -- read single sample from channel</DIV
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>Synopsis</H2
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>#include <comedilib.h></PRE
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><CODE
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>int comedi_data_read</CODE
>(comedi_t * device, unsigned int subdevice, unsigned int channel, unsigned int range, unsigned int aref, lsampl_t * data);</CODE
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> Description
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>Reads a single sample on the channel specified by the Comedi
device device, the subdevice subdevice, and the channel channel.
For the A/D conversion (if appropriate),
the device is configured to use range specification
range and (if appropriate) analog reference type
aref. Analog reference types that are not supported
by the device are silently ignored.</P
><P
>The function comedi_data_read() reads one data value from
the specified channel and places the data value in the
location pointed to by data.</P
><P
>WARNING: comedi_data_read() does not do any pausing to
allow multiplexed analog inputs to settle before
performing an analog to digital conversion. If you are
switching between different channels and need to allow
your analog input to settle for an accurate reading,
use comedi_data_read_delayed(), or set the
input channel at an earlier time with
comedi_data_read_hint().</P
><P
>On sucess, comedi_data_read() returns 1 (the number of samples
read). If there is an error, -1 is returned.</P
><P
>Data values returned by this function are unsigned integers
less than or equal to the maximum sample value of the channel,
which can be determined using the function comedi_get_maxdata().
Conversion of data values to physical units can be performed
by the function comedi_to_phys().</P
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