ADLINK PXI-2006 - Manual (Page 58)

48 Operation Theory
Iterative Waveform Generation
Set IC_Counter in order to generate iterative waveforms from
the data of a single waveform. The counter stores the iteration
number, and the itera-tions can be finite (Figure 4-12) or infinite
(Figure 4-13).
A data FIFO on board is used to buffer the digital data for DA
output. If the data size of a single waveform you specified (That
is, Update Counts in UC_counter) is less than the FIFO size,
after initially transferring the data from the host PC memory to
the FIFO on board, the data in the FIFO will be automatically
re-transmitted whenever a single waveform is completed.
Therefore, it won’t occupy the PCI bandwidth when repetitive
waveforms are performed. However, if the size of a single
waveform were larger than that of the FIFO, it needs to be
intermittently loaded from the host PC’s memory via DMA,
when a repetitive waveforms is performed thus PCI bandwidth
would be occupied.
The data FIFO size on DAQ/PXI-2010 is 2k samples and on
DAQ/PXI-2005/2006/2016 it is 512 samples.
Figure 4-18: Finite iterative waveform generation with Post-trigger and
DLY2_Counter = 0 (Assuming the data in the data buffer are 2V, 4V, 2V, 0V)