ARM R4F Computer Hardware User Manual


 
Processor Initialization, Resets, and Clocking
ARM DDI 0363E Copyright © 2009 ARM Limited. All rights reserved. 3-6
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3.2 Resets
The processor has the following reset inputs:
nRESET This signal is the main processor reset that initializes the majority of the
processor logic.
PRESETDBGn This signal resets processor debug logic and CoreSight ETM-R4.
nSYSPORESET This signal is the reset that initializes the entire processor, including CP14
debug logic and the APB debug logic. See CP14 registers reset on page
11-23 for information.
nCPUHALT This signal stops the processor from fetching instructions after reset.
All of these are active-LOW signals that reset logic in the processor. You must take care when
designing the logic to drive these reset signals.
The processor synchronizes the resets to the relevant clock domains internally.