UEi PowerDAQ PDXI-AO Series, User Manual

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Chapter 3: Architecture
23
Auto-regeneration Waveform (circular waveform)
Auto-regeneration waveform mode can be used to create
fixed length waveforms without any host intervention of
user software after the subsystem has initialized. An
application writes data to the buffer of the PowerDAQ AO
board and each time the end of buffer is reached, it starts
to resend the same buffer again. Note, that 2048 samples
can fit into the on-board DSP memory and auto
regeneration of up to 2048 samples will not require any
intervention of the host PC.
Channel List
There are two ways do define a Channel List for the
PowerDAQ AO board. First, when the output data and
channel number are combined together to provide the
output channel selection. In this situation, the lower 16 bits
are data, the following upper 8, the channel number and
special flags (see the picture below).
This mode supports update rates up to 455KS/sec
31 23 15 0
Bits 16-20 are used to define the output channel number on
a
PD2/PDXI-AO-8[16][32]
board.
Bit 21, when set is used as a Write and Hold Flag – this is
used to write data to the DAC WITHOUT updating it on a
PD2/PDXI-AO-8[16][32]
board.
Bit 22, when set is used as an Update All Flag – all DAC’s
will be updated by the previously written data on a
PD2/PDXI-AO-8[16][32] board.
PD2-AO-96 board only:
Bits 16-22 are used to define the output channel number on
PD2/PDXI-AO-8[16][32]
boards.
Not used 16-bit output data Flags,
Ch#