MC68HC705P9 Datasheet, PDF (67/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Low-Power Modes
Stop Mode
Figure 2 shows the sequence of events caused by the STOP instruction.
STOP
CLEAR I BIT IN CCR
CLEAR TIMER INTERRUPT FLAGS AND TIMER INTERRUPT ENABLE BITS
CLEAR TIMER PRESCALER
TURN OFF OSCILLATOR
NO
EXTERNAL
NO
INTERRUPT?
YES
RESET?
YES
TURN ON OSCILLATOR
DELAY 4064 CYCLES
TO STABILIZE
(1) LOAD PC WITH RESET VECTOR
OR
(2) SERVICE INTERRUPT
a. SAVE CPU REGISTERS ON STACK
b. SET I BIT IN CCR
c. LOAD PC WITH INTERRUPT VECTOR
Figure 2. STOP Instruction Flowchart
3-mc68hc705p9
MOTOROLA
Low-Power Modes
67