National Instruments AT-MIO-16X - Manual (Page 177)

Chapter 5 Programming
AT-MIO-16X User Manual 5-8 © National Instruments Corporation
In posttrigger sequences, the sample counter starts counting after
receipt of the first trigger, while in the pretrigger acquisition mode, the
sample counter does not start counting until a second trigger condition
occurs. The data acquisition operation is initiated by writing to the
DAQ Start Register or by a falling edge on the EXTTRIG* signal.
Programming multiple A/D conversions on a single channel requires
the following programming steps for posttrigger and pretrigger modes,
as well as internal and external timing. The instructions in the blocks of
the following flow chart are enumerated in the Data Acquisition
Programming Functions section later in this chapter.