User`s manual

X5-GSPS XMC Module
Framed Trigger Mode
Framed trigger mode is useful for collecting data sets of a fixed size each time the input trigger is fired. In framed mode, the
trigger goes false once the programmed number of points N have been collected. Start triggers that occur during a frame
trigger are ignored.
The maximum number of points per frame is 16,777,216 (2^24) points, while the minimum number of points is 8. Frame size
must be a multiple of 8 on the X5-GSPS.
Data flow to the host is independent of the framed triggering mode. In most cases, packet sizes to the host are selected to be
integer submultiples of the frame size to allow the entire data set to flow to the host. That way, the entire data frame can be
moved immediately to the host without waiting for the next trigger frame.
Decimation
The data may be decimated by a programmed ratio to reduce the data rate. This mode is usually used when the data rate is less
than the minimum master clock rate of the A/D. A/D performance is not specified and will degrade (sometimes with
unpredictable results) if the converter is operated below its minimum sample rate.
The decimation simply discards M points for every point kept – no averaging or filtering is used. When decimation is true, the
number of points captured in the framed mode is the number of decimated points, in other words the discarded points do not
count. Maximum decimation rate is 1/4095.
When decimation is used in the framed trigger mode, the number of points captured is after decimation. The frame count is
always the actual number of points inserted into the FIFO.
FrameWork Logic Functionality
The FrameWork Logic implements a data flow for the X5-GSPS that supports standard data acquisition functionality. This
data flow, when used with the supporting software, allows the X5-GSPS to act as a data acquisition card with 512MB of data
buffering and high speed data streaming to the host PCI Express. The example software for the X5-GSPS demonstrates data
flow control, logic loading and data logging.
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