Datasheet

Clock Functions
Technical Data MC68HC912D60A — Rev. 3.1
154 Clock Functions Freescale Semiconductor
11.6.11 Pseudo-STOP exit without Limp Home mode, clock monitor enabled
(NOLHM=1, CME=1, DLY=X)
If the NOLHM bit is set and the CME (or FCME) bits are set, a clock
monitor failure is detected when a STOP instruction is executed and the
MCU resets via the clock monitor reset vector.
11.6.12 Pseudo-STOP exit without Limp Home mode, clock monitor disabled
(NOLHM=1, CME=0, DLY=1)
If NOLHM is set to 1 and the CME and FCME bits are cleared, the limp
home clock is not used. In this mode, crystal activity is the only method
by which the device may recover from Pseudo-STOP. The device will
start execution with the EXTALi clock following 4096 XCLK cycles.
(NOLHM=1, CME=0, DLY=0)
If NOLHM is set to 1 and the CME and FCME bits are cleared, the limp
home clock is not used. In this mode, crystal activity is the only method
by which the device may recover from Pseudo-STOP. The device will
start execution with the EXTALi clock following 16 XCLK cycles.
CAUTION: Due to switching of the clock this configuration is not recommended.
11.6.13
11.6.14 Summary of STOP and pseudo-STOP Mode Exit Conditions
Table 11-1 and Table 11-2 summarise the exit conditions from STOP
and pseudo-STOP modes using Interrupt, Key-interrupt and XIRQ.
A short RESET pulse should not be used to exit stop or pseudo-STOP
mode because Limp Home mode is automatically entered after RESET
(when V
DDPLL
=V
DD
). The RESET wakeup pulse must be longer than the
oscillator startup time (as in power on reset) in order to remove the risk
of code runaway.