MC908GZ60CFUE Datasheet, PDF (129/352 Pages) Freescale Semiconductor, Inc – Standard features, Features of the CPU08

Exiting Stop Mode
• MSCAN module interrupt — A CPU interrupt request from the MSCAN08 loads the program
counter with the contents of:
– $FFD4 and $FFD5; MSCAN08 transmitter
– $FFD6 and $FFD7; MSCAN08 receiver
– $FFD8 and $FFD9; MSCAN08 error
– $FFDA and $FFDB; MSCAN08 wakeup
10.16 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 low 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-to-high transition when KBIPx bits are set)
• Low-voltage inhibit (LVI) reset — A power supply voltage below the V_TRIPF voltage resets the MCU
and loads the program counter with the contents of locations $FFFE and $FFFF.
• Break interrupt — In emulation mode, a break interrupt loads the program counter with the contents
of locations $FFFC and $FFFD.
• Timebase module (TBM) interrupt — A TBM interrupt loads the program counter with the contents
of locations $FFDC and $FFDD when the timebase counter has rolled over. This allows the TBM
to generate a periodic wakeup from stop mode.
• MSCAN08 interrupt — MSCAN08 bus activity can wake the MCU from CPU stop. However, until
the oscillator starts up and synchronization is achieved the MSCAN08 will not respond to incoming
data.
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 CGMXCLK 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 CGMXCLK cycles to 32
CGMXCLK cycles.
NOTE
Use the full stop recovery time (SSREC = 0) in applications that use an
external crystal unless the OSCENINSTOP bit is set.
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Freescale Semiconductor
129