Agilent Technologies 93000 SOC Series Training Manual page 330

Lesson 3 – Setting Up the Digital Capturing
Setting up the Timing for Sequential Capturing
When using the Sequential Capture Mode, capturing will be
performed on
edge 1 in Standard Mode
•
edge 1 and edge 4 in Double Mode
•
This means, that you have to set up an edge compare on these
edges to define when the data of the pin is to be captured.
Capturing will be performed at every vector of a vector label. This
is the reason why this mode is called Sequential Mode.
If the captured data of some vectors is not needed, it can be
filtered out later by the vector variable.
The figure below shows a typical timing for digital capture pins,
using Standard Mode.
Alternatively, you can set up a corresponding wave table for
capturing, when using equation based setup.
Example of Timing Setup for Digital Capture
Please note that for all capture pins in the figure above edge 1 is
set up as "compare to low". This is good practice when capturing
data. However, for the capture result, it is of no significance
whether a compare to high or to low is used.
The following list summarizes some further points to consider and
some tips for an efficient use of Digital Capture.
If you do not explicitly set up edge 1 (and edge 4 in Double Mode)),
•
data capturing will still be performed at time zero of the cycle, as
by default each undefined edge is positioned at 0.
When using Double Mode, the edges 1 and 4 must placed with a
•
minimum distance of half a tester period.
It is advisable to define a device cycle called "cap" or similar, that
•
only contains the waveform for capturing.
This helps when defining the vectors.
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