Freescale Semiconductor, Inc.
Clock Functions
Therefore, if the MCU is powered up without an external clock, limp-
home mode is entered provided the MCU is in a normal mode of
operation.
VDD
Power-On Detector
EXTALi
(Slow EXTALi)
Clock Monitor Fail
Limp-Home
0 --> 4096
0 --> 4096
13-stage counter
(Clocked by XCLK)
BCSP
Reset: BCSP = 0
Internal reset
SYSCLK
PLLCLK (L.H.)
EXTALi
SYSCLK
PLLCLK (Software check of Limp-Home Flag)
EXTALi
(Slow EXTALi)
Figure 11-4. No Clock at Power-On Reset
Technical Data
MC68HC912DG128 — Rev 3.0
Clock Functions
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