mc68hc908bd48 Freescale Semiconductor, Inc, mc68hc908bd48 Datasheet - Page 105

• Manufacturer Part Number: mc68hc908bd48
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

7.7 Low-Power Modes
7.7.1 Wait Mode
MC68HC908BD48
Freescale Semiconductor
—
Rev. 2.1
Executing the WAIT or STOP instruction puts the MCU in a low-power-
consumption mode for standby situations. The SIM holds the CPU in a
non-clocked state. The operation of each of these modes is described
below. Both STOP and WAIT clear the interrupt mask (I) in the condition
code register, allowing interrupts to occur.
In wait mode, the CPU clocks are inactive while the peripheral clocks
continue to run.
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. A break interrupt
during wait mode sets the SIM break stop/wait bit, SBSW, in the SIM
break status register (SBSR). If the COP disable bit, COPD, in
configuration register 1 (CONFIG1) is logic zero, then the computer
operating properly module (COP) is enabled and remains active in wait
mode.
Figure 7-14
R/W
IDB
IAB
NOTE: Previous data can be operand data or the WAIT opcode, depending on the last instruction.
System Integration Module (SIM)
WAIT ADDR
and
Figure 7-13. Wait Mode Entry Timing
Figure 7-13
Figure 7-15
PREVIOUS DATA
WAIT ADDR + 1
shows the timing for wait mode entry.
show the timing for WAIT recovery.
NEXT OPCODE
SAME
System Integration Module (SIM)
SAME
SAME
SAME
Data Sheet
105