| 摘要 |
An on-chip trace engine stores trace data in on-chip trace arrays and routes the trace data to output pins. An external trace capture device captures the trace data. The on-chip trace engine streams the trace data through the debug output pins at a slower rate that can be supported by external trace capture device. If compression is insufficient for the required data rate reduction, the on-chip trace engine includes selectable data reduction mechanisms. Responsive to an overflow condition, meaning trace data is captured in on-chip trace arrays faster than it can be routed off chip, the on-chip trace engine enters an overflow mode in which one or more of the data reduction mechanisms are selected. The data reduction mechanisms may include, for example, a data width reduction component, a pattern match data elimination component, a priority source select component, an under-sampling component, or various combinations thereof.
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