User manual

Chapter 3 Software Overview
© National Instruments Corporation 3-59 NI-DAQ User Manual for PC Compatibles
DIG_Out_Grp
Writes digital output data to the specified
digital group.
DIG_SCAN_Setup
Configures the specified group for port
assignment, direction (input or output),
and size.
DIG_Trigger_Config
Enables or disables the trigger mode of
buffered digital I/O to indicate when to
start and stop the data acquisition.
Double-Buffered Digital I/O Functions
The double-buffered digital I/O (
DIG_DB
) functions perform
double-buffered operations during Group Digital I/O operations.
Refer to the NI-DAQ Function Reference Online Help file to determine
which functions your device supports.
DIG_DB_Config
Enables or disables double-buffered
digital transfer operations and sets the
double-buffered options.
DIG_DB_HalfReady
Checks whether the next half buffer of data
is available during a double-buffered
digital block operation. You can use
DIG_DB_HalfReady
to avoid the possible
waiting period that can occur because
DIG_DB_Transfer
waits until the data
can be transferred before returning.
DIG_DB_Transfer
For an input operation,
DIG_DB_Transfer
waits until NI-DAQ
can transfer half the data from the buffer
being used for double-buffered digital
block input to another buffer, which is
passed to the function. For an output
operation,
DIG_DB_Transfer
waits
until NI-DAQ can transfer the data from
thebufferpassedtothefunctiontothe
buffer being used for double-buffered
digital block output. You can execute
DIG_DB_Transfer
repeatedly to read
or write sequential half buffers of data.