System Integration Module (SIM)
IAB
IDB
WAIT ADDR
WAIT ADDR + 1
SAME
SAME
PREVIOUS DATA
NEXT OPCODE
SAME
SAME
R/W
NOTE: Previous data can be operand data or the WAIT opcode, depending on the
last instruction.
Figure 7-15. Wait Mode Entry Timing
Figure 7-16 and Figure 7-17 show the timing for WAIT recovery.
IAB
$6E0B
$6E0C
$00FF
$00FE
$00FD
$00FC
IDB
$A6
$A6
$A6
$01
$0B
$6E
EXITSTOPWAIT
NOTE: EXITSTOPWAIT = RST pin OR CPU interrupt OR break interrupt
Figure 7-16. Wait Recovery from Interrupt or Break
32
CYCLES
32
CYCLES
IAB
$6E0B
$A6
RST VCT H RST VCT L
IDB $A6
RST
$A6
ICLK
Figure 7-17. Wait Recovery from Internal Reset
7.6.2 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 or break also causes an exit from stop mode.
The SIM disables the clock generator module output (CGMOUT) in stop mode, stopping the CPU and
peripherals. Stop recovery time is selectable using the SSREC bit in the configuration register 1
(CONFIG1). If SSREC is set, stop recovery is reduced from the normal delay of 4096 ICLK cycles down
to 32. This is ideal for applications using canned oscillators that do not require long start-up times from
stop mode.
NOTE
External crystal applications should use the full stop recovery time by
clearing the SSREC bit.
MC68HC908AP Family Data Sheet, Rev. 4
110
Freescale Semiconductor
FREESCALE [ Freescale ]
