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.TH "COMEDI_DATA_READ" "3" "02 October 2004" "" ""
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comedi_data_read \- read single sample from channel
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\fB#include <comedilib.h>
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int comedi_data_read (comedi_t * \fIdevice\fB, unsigned int \fIsubdevice\fB, unsigned int \fIchannel\fB, unsigned int \fIrange\fB, unsigned int \fIaref\fB, lsampl_t * \fIdata\fB);
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Reads a single sample on the channel specified by the Comedi
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device device, the subdevice subdevice, and the channel channel.
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For the A/D conversion (if appropriate),
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the device is configured to use range specification
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range and (if appropriate) analog reference type
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aref. Analog reference types that are not supported
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by the device are silently ignored.
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The function comedi_data_read() reads one data value from
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the specified channel and places the data value in the
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location pointed to by data.
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WARNING: comedi_data_read() does not do any pausing to
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allow multiplexed analog inputs to settle before
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performing an analog to digital conversion. If you are
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switching between different channels and need to allow
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your analog input to settle for an accurate reading,
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use comedi_data_read_delayed(), or set the
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input channel at an earlier time with
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comedi_data_read_hint().
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On sucess, comedi_data_read() returns 1 (the number of samples
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read). If there is an error, -1 is returned.
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Data values returned by this function are unsigned integers
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less than or equal to the maximum sample value of the channel,
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which can be determined using the function comedi_get_maxdata().
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Conversion of data values to physical units can be performed
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by the function comedi_to_phys().
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doc/man/comedi_data_read.3
