NTRST is the TAP controller
reset. It is used within the ETM10 as the main reset signal for
both TCK and GCLK domain
logic. ETM10 uses NTRST rather
than the core reset signal so that you can trace the core through
reset. Deassertion of the main NTRST input
can be asynchronous to both TCK and GCLK, and TCK and GCLK are asynchronous clock domains,
so NTRST is synchronized internally
for deassertion for both the TCK and GCLK domains. Assertion of NTRST is asynchronous.
Note
NTRST must be asserted
for at least eight cycles when the system is initially powered on,
otherwise the behavior of the ETM and of the whole system is unpredictable.
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