摘要 |
A series of secondary or "shadow" storage elements are employed that duplicate, or "shadow", the information in a circuit's core logic shadowed functional registers. These shadow storage elements are then coupled to form a separate, independently-addressable shadow scan path. The information contained in the shadowed functional registers of a circuit is then shifted out via the shadow scan path without altering the shadowed functional registers using special commands issued from a JTAG controller.
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