
System Integration Module (SIM)
Low-Power Modes
MC68HLC908QY/QT Family — Rev. 2
Data Sheet
MOTOROLA
System Integration Module (SIM)
125
A module that is active during wait mode can wake up the CPU with an interrupt if
the interrupt is enabled. Stacking for the interrupt begins one cycle after the WAIT
instruction during which the interrupt occurred. In wait mode, the CPU clocks are
inactive. Refer to the wait mode subsection of each module to see if the module is
active or inactive in wait mode. Some modules can be programmed to be active in
wait mode.
Wait mode can also be exited by a reset (or break in emulation mode). A break
interrupt during wait mode sets the SIM break stop/wait bit, SBSW, in the break
status register (BSR). If the COP disable bit, COPD, in the configuration register
is 0, then the computer operating properly module (COP) is enabled and remains
active in wait mode.
Figure 13-16. Wait Recovery from Interrupt
Figure 13-17. Wait Recovery from Internal Reset
13.7.2 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 or break
also causes an exit from stop mode.
$6E0C
$6E0B
$00FF
$00FE
$00FD
$00FC
$A6
$01
$0B
$6E
$A6
ADDRESS BUS
DATA BUS
EXITSTOPWAIT
NOTE: EXITSTOPWAIT = RST pin OR CPU interrupt
ADDRESS BUS
DATA BUS
RST(1)
$A6
$6E0B
RSTVCTH
RSTVCTL
$A6
BUSCLKX4
32
CYCLES
32
CYCLES
1. RST is only available if the RSTEN bit in the CONFIG1 register is set.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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