MC908AZ60ACFUER Datasheet, PDF (123/414 Pages) Freescale Semiconductor, Inc – To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to:

Low-Power Modes
9.6.2 Stop Mode
In stop mode, the SIM counter is reset and the system clocks are disabled. An interrupt request from a
module can cause an exit from stop mode. Stacking for interrupts begins after the selected stop recovery
time has elapsed. Reset also causes an exit from stop mode.
The SIM disables the clock generator module outputs (CGMOUT and CGMXCLK) in stop mode, stopping
the CPU and peripherals. Stop recovery time is selectable using the SSREC bit in the configuration
register (CONFIG-1). If SSREC is set, stop recovery is reduced from the normal delay of 4096 CGMXCLK
cycles down to 32. This is ideal for applications using canned oscillators that do not require long startup
times from stop mode.
NOTE
External crystal applications should use the full stop recovery time by
clearing the SSREC bit.
The break module is inactive in Stop mode. The STOP instruction does not affect break module register
states.
The SIM counter is held in reset from the execution of the STOP instruction until the beginning of stop
recovery. It is then used to time the recovery period. Figure 9-15 shows stop mode entry timing.
NOTE
To minimize stop current, all pins configured as inputs should be driven to
a logic 1 or logic 0.
CPUSTOP
IAB
STOP ADDR
STOP ADDR + 1
SAME
SAME
IDB
PREVIOUS DATA
NEXT OPCODE
SAME
SAME
R/W
NOTE: Previous data can be operand data or the STOP opcode, depending on the last
instruction.
Figure 9-15. Stop Mode Entry Timing
CGMXCLK
INT/BREAK
IAB
STOP RECOVERY PERIOD
STOP +1
STOP + 2 STOP + 2
SP
SP – 1
SP – 2
SP – 3
Figure 9-16. Stop Mode Recovery from Interrupt or Break
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
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