ChipScope Pro Software and Cores User Guide
15
UG029 (v14.3) October 16, 2012
ChipScope Pro Cores Description
ILA Data Capture Logic
Each ILA core can capture data using on-chip block RAM resources independently from all
other cores in the design. Each ILA core can also capture data using one of two capture
modes:
Window
and
N sample
s.
Window Capture Mode
In Window capture mode, the sample buffer can be divided into one or more equal-sized
sample windows. The window capture mode uses a single trigger condition event (i.e., a
Boolean combination of the individual trigger match unit events) to collect enough data to
fill a sample window.
In the case where the depth of the sample windows is a power of 2 up to 131,072 samples,
the trigger position can be set to the beginning of the sample window (trigger first, then
collect), the end of the sample window (collect until the trigger event), or anywhere in
between.
In the other case where the window depth is
not
a power of 2, the trigger position can only
be set to the beginning of the sample window.
After a sample window has been filled, the trigger condition of the ILA core is
automatically re-armed and continues to monitor for trigger condition events. This process
is repeated until all sample windows of the sample buffer are filled or until you halt the
ILA core.
N Samples Capture Mode
The N Samples capture mode is similar to the Window capture mode except for two major
differences:
•
The number of samples per window can be any integer N from 1 to the sample buffer
size minus 1.
•
The trigger position must always be at position 0 in the window.
The N sample capture mode is useful for capturing the exact number of samples needed
per trigger without wasting valuable capture storage resources.
Trigger Marks
The data sample in the sample window that coincides with a trigger event is tagged with
a trigger mark. This trigger mark tells the ChipScope Pro Analyzer tool the position of the
trigger within the window. This trigger mark consumes one extra bit per sample in the
sample buffer.
Data Port
The ILA core provides the capability to capture data on a port that is separate from the
trigger ports that are used to perform trigger functions. This feature is useful for limiting
the amount of data to be captured to a relatively small amount because it is not always
useful to capture and view the same information that is used to trigger the core.
However, in many cases it is useful to capture and view the same data that is used to
trigger the core. In this case, you can choose for the data to consist of one or more of the
trigger ports. This feature allows you to conserve resources while providing the flexibility
to choose what trigger information is interesting enough to capture.
