
Clock Functions
Advance Information
68HC(9)12D60 — Rev 4.0
152
Clock Functions
MOTOROLA
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.
Figure 12-4. No Clock at Power-On Reset
VDD
Power-On Detector
Clock Monitor Fail
EXTALi
13-stage counter
Internal reset
0 --> 4096
Limp-Home
(Clocked by XCLK)
BCSP
Reset: BCSP = 0
SYSCLK
PLLCLK (L.H.)
EXTALi
SYSCLK
PLLCLK (Software check of Limp-Home Flag)
EXTALi
(Slow EXTALi)
0 --> 4096
(Slow EXTALi)