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Chapter 2 Function Reference — WFM_DB_HalfReady
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National Instruments Corporation 2-413 NI-DAQ FRM for PC Compatibles
WFM_DB_HalfReady
Format
status = WFM_DB_HalfReady (deviceNumber, numChans, chanVect, halfReady)
Purpose
Checks if the next half buffer for one or more channels is available for new data during a
double-buffered waveform generation operation. You can use
WFM_DB_HalfReady to avoid
the waiting period that can occur with the double-buffered transfer functions.
Parameters
Input
Output
Parameter Discussion
numChans indicates the number of analog output channels specified in the array chanVect.
chanVect is the user array of channel numbers indicating which analog output channels are
to be checked to see if the next half buffer for that channel is available.
Channel number range:
0 or 1 for most devices.
0 through 5 for AT-AO-6.
0 through 9 for AT-AO-10.
halfReady indicates whether the next half buffer for all of the channels specified in chanVect
is available for new data. When halfReady equals 1, you can use
WFM_DB_Transfer to write
new data to the next half buffer(s) immediately. When halfReady equals 0, the next half
buffer for one or more channels is not ready for new data.
Note
C Programmers—halfReady is a pass-by-reference parameter.
Name Type Description
deviceNumber i16 assigned by configuration utility
numChans i16 number of analog output channels
chanVect [i16] channel numbers
Name Type Description
halfReady i16 whether the next half buffer is available for new
data