Signal Properties And Requirements - ARM ARM926EJ-S Technical Reference Manual

Signal Descriptions
A.1

Signal properties and requirements

A-2
To ensure ease of integration of the ARM926EJ-S processor into embedded
applications, and to simplify synthesis flow, the following design techniques have been
used:
• a single rising edge clock times all activity
• all signals and buses are unidirectional
• all inputs are required to be synchronous to the single clock.
These techniques simplify the definition of the top-level ARM926EJ-S processor
signals because all outputs change from the rising edge and all inputs are sampled with
the rising edge of the clock. In addition, all signals are either input or output only.
Bidirectional signals are not used.
Note
You must use external logic to synchronize asynchronous signals (for example interrupt
sources) before applying them to the ARM926EJ-S processor.
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