MC68HC705MC4 Datasheet, PDF (23/99 Pages) Motorola, Inc – Microcontrollers

MC68HC705MC4 Specification Rev. 1.5
NOTE:
Execution of the STOP instruction with STOP enabled (via Mask Option)
will cause the oscillator to stop, and therefore disable the COP watchdog
timer. If the COP watchdog timer is to be used, the Stop mode should be
disabled by selecting the appropriate Mask Option.
2.4.2 WAIT INSTRUCTION
The WAIT instruction places the MCU in a low-power mode, which consumes more power
than the stop mode. In Wait mode, the bus clock is halted, suspending all processor and
internal bus activity but the timer, PWM, A/D, SCI, and COP subsystems remain active.
The user may optionally disable each individual subsystem through software before
entering Wait mode in order to save more power. Execution of the WAIT instruction
automatically clears the I-bit in the Condition Code Register enabling the IRQ external
interrupt. All other registers, memory, and input/output lines remain in their previous state
unless modified by an active peripheral.
If the 16-bit timer interrupt is enabled it will cause the processor to exit the Wait Mode and
resume normal operation. The 16-bit timer may be used to generate a periodic exit from
the Wait Mode. The Wait Mode may also be exited when an IRQ external interrupt, SCI
interrupt, or RESET occurs.
MOTOROLA
Page 14
Section 2: Operating Modes