Freescale Semiconductor, Inc.
GENERAL RELEASE SPECIFICATION
SECTION 5
RESETS
The MCU can be reset three ways: by the initial power-on reset function, by an
active low input to the RESET pin, and by a computer operating properly (COP)
watchdog-timer timeout.
5.1
Power-On Reset (POR)
An internal reset is generated on power-up to allow the internal clock generator to
stabilize. The power-on reset is strictly for power turn-on conditions and should
not be used to detect a drop in the power supply voltage.
There is a 4064 internal processor clock cycle (t ) oscillator stabilization delay
cyc
after the oscillator becomes active. If the RESET pin is low at the end of this 4064-
cycle delay, the MCU will remain in the reset condition until RESET goes high.
5.2
5.3
RESET Pin
The MCU is reset when a logic zero is applied to the RESET input for a period of
one and one-half machine cycles (t ).
cyc
Computer Operating Properly (COP) Reset
The MCU contains a watchdog timer that automatically times out if not reset
Rev. 2.0
5-1
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