s908gr32ag3vfa Freescale Semiconductor, Inc, s908gr32ag3vfa Datasheet - Page 198

• Manufacturer Part Number: s908gr32ag3vfa
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

System Integration Module (SIM)
14.6.2 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 CONFIG1. 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.
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.
14-20
198
shows stop mode recovery time from interrupt.
CGMXCLK
INT/BREAK
IAB
External crystal applications should use the full stop recovery time by
clearing the SSREC bit unless OSCENINSTOP bit is set in CONFIG2.
To minimize stop current, all pins configured as inputs should be driven to
a 1 or 0.
Note: Previous data can be operand data or the STOP opcode, depending on the last instruction.
CPUSTOP
MC68HC908GR60A • MC68HC908GR48A • MC68HC908GR32A Data Sheet, Rev. 5
R/W
IDB
IAB
Figure 14-20. Stop Mode Recovery from Interrupt
STOP ADDR
STOP +1
Figure 14-19. Stop Mode Entry Timing
PREVIOUS DATA
STOP ADDR + 1
STOP + 2
STOP RECOVERY PERIOD
NOTE
NOTE
NEXT OPCODE
Figure 14-19
STOP + 2
SAME
shows stop mode entry timing.
SP
SAME
SP – 1
SAME
SAME
Freescale Semiconductor
SP – 2
SP – 3
Figure