MC912DG128A Motorola, MC912DG128A Datasheet - Page 151

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

Pseudo-STOP exit
without Limp
Home mode,
clock monitor
enabled
Pseudo-STOP exit
without Limp
Home mode,
clock monitor
disabled
Summary of STOP
and pseudo-STOP
Mode Exit
Conditions
17-clock
MOTOROLA
CAUTION:
(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.
(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.
Due to switching of the clock this configuration is not recommended.
Table 23
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
oscillator startup time (as in power on reset) in order to remove the risk
of code runaway.
DDPLL
and
Table 24
=V
DD
Clock Functions
). The RESET wakeup pulse must be longer than the
summarise the exit conditions from STOP and
Limp-Home and Fast STOP Recovery modes
MC68HC912DT128A Rev 2.0
Clock Functions
151