ADLINK PXI-2502 - Manual (Page 34)

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• Operation Theoreym
Hardware controlled Waveform Generation
FIFO is a hardware first-in first-out data queue, which holds temporary
digital codes for D/A conversion. When DAQ/PXI-2500 SERIES operates
in Waveform Generation mode, the waveform patterns are stored in FIFO,
with 8K maximum samples. Waveform patterns larger than 8K are also
supported by utilizing bus-mastering DMA transfer supported by PCI con-
troller. Data format in FIFO is shown in Figure 4.2.2.
Figure 4.2.2 Data Format in FIFO and mapping
With hardware-based Waveform Generation, D/A conversions are updated
automatically by CPLD rather than application software. Unlike the con-
ventional Software-based Waveform Generation, the precise hardware
timing control guarantees non-distorted waveform generation even when
host CPU is under heavy loading. D etailed function setup will be explained
in Section 4.2.2.
NOTE: When using waveform generation mode, all the four DACs in the
same D/A group must be configured for the same mode. However, any
one of the DAC can be disabled. If users need to use the software update
mode, they can use another D/A group on the PXI/DAQ-2502.