MC68HC05L28 Datasheet, PDF (32/156 Pages) Motorola, Inc – Flexible general-purpose microcomputer

2.3
2
Low power modes
2.3.1 STOP
The STOP instruction places the MCU in its lowest power consumption mode. In STOP mode, the
internal oscillator is turned off, halting all internal processing, including timer (and COP watchdog
timer) operation.
During the STOP mode, the core timer interrupt flags (CTOF and RTIF) and interrupt enable bits
(CTOFE and RTIE) in the CTCSR are cleared by internal hardware. This removes any pending
timer interrupt requests and disables any further timer interrupts. The timer prescaler is also
cleared. The I-bit in the CCR is cleared to enable external interrupts. All other registers, the
remaining bits in the CTCSR, and memory contents remain unaltered. All input/output lines remain
unchanged. The processor can be brought out of the STOP mode only by an external interrupt or
a reset (see Figure 2-5).
The STOP instruction can be disabled by a mask option. When disabled, it is executed as a NOP.
MOTOROLA
2-10
MODES OF OPERATION AND PIN DESCRIPTIONS
TPG
MC68HC05L28