MC68HC908LB8_05 Datasheet, PDF (118/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Low-Power Modes
11.15 Exiting Stop Mode
These events restart the system clocks and load the program counter with the reset vector or with an
interrupt vector:
• External reset — A logic 0 on the RST pin resets the MCU and loads the program counter with the
contents of locations $FFFE and $FFFF.
• External interrupt — A high-to-low transition on an external interrupt pin loads the program counter
with the contents of locations:
– $FFFA and $FFFB; IRQ pin
– $FFE0 and $FFE1; keyboard interrupt pins
• Low-voltage inhibit (LVI) reset — A power supply voltage below the LVI_TRIPF voltage resets the
MCU and loads the program counter with the contents of locations $FFFE and $FFFF.
• Break (BRK) interrupt — A break interrupt loads the program counter with the contents of locations
$FFFC and $FFFD.
• Keyboard (KBI) interrupt — A keyboard interrupt loads the program counter with contents of
location $FFE0 and $FFE1.
Upon exit from stop mode, the system clocks begin running after an oscillator stabilization delay. A 12-bit
stop recovery counter inhibits the system clocks for 4096 BUSCLKX4 cycles after the reset or external
interrupt.
The short stop recovery bit, SSREC, in the CONFIG1 register controls the oscillator stabilization delay
during stop recovery. Setting SSREC reduces stop recovery time from 4096 BUSCLKX4 cycles to 32
BUSCLKX4 cycles.
NOTE
Use the full stop recovery time (SSREC = 0) in applications that use an
external crystal.
MC68HC908LB8 Data Sheet, Rev. 1
118
Freescale Semiconductor