mc68hc705j2 Freescale Semiconductor, Inc, mc68hc705j2 Datasheet - Page 45

• Manufacturer Part Number: mc68hc705j2
• Description: 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

4.5.2 WAIT Mode
MC68HC705J2
The WAIT instruction puts the MCU in an intermediate power-consumption
mode. In WAIT mode, the following events occur:
The WAIT instruction does not affect any other registers or any I/O lines. The
timer and COP timer remain active in WAIT mode.
The following conditions bring the MCU out of WAIT mode:
A COP timer reset or a reset signal on the RESET pin automatically loads the
program counter with the contents of locations $0FFE and $0FFF, the locations
of the vector address of the reset service routine.
Figure 4-3 shows the sequence of events caused by the WAIT instruction.
• All CPU clocks stop.
• The CPU clears the interrupt mask in the condition code register,
• A timer interrupt. If a real-time interrupt or a timer overflow interrupt
• An external interrupt.
• A COP timer reset. A timeout of the COP timer during WAIT mode resets
• A reset signal on the RESET pin during WAIT mode resets the MCU.
enabling external interrupts and timer interrupts.
occurs during WAIT mode, the MCU loads the program counter with the
contents of locations $0FF8 and $0FF9, the locations of the vector
address of the timer interrupt service routine.
program counter with the contents of locations $0FFA and $0FFB, the
locations of the vector address of the external interrupt service routine.
the MCU. The programmer can enable real-time interrupts so the MCU
can periodically exit WAIT mode to reset the COP timer.
CENTRAL PROCESSOR UNIT
An external interrupt automatically loads the
MOTOROLA
4-25