MC68HC05P18A Datasheet, PDF (52/130 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Operating Modes
Freescale Semiconductor, Inc.
6.4.1 STOP Instruction
The STOP instruction can result in one of two modes of operation,
depending on the mask option.
1. If the stop conversion to halt mask option is not chosen, the STOP
instruction behaves like a normal STOP instruction in the
M68HC05 Family and places the MCU in stop mode.
2. If the stop conversion to halt mask option is chosen, the STOP
instruction behaves like a WAIT instruction (with the exception of
a brief delay at startup) and places the MCU in halt mode.
6.4.1.1 Stop Mode
Execution of the STOP instruction without conversion to halt places the
MCU in its lowest power consumption mode. In stop mode, the internal
oscillator is turned off, halting all internal processing, including the COP
watchdog timer. The RC oscillator that feeds the electrically erasable
programmable read-only memory (EEPROM) and the A/D converter is
also stopped. Execution of the STOP instruction automatically clears the
I bit in the condition code register so that the IRQ external interrupt is
enabled. All other registers and memory remain unaltered. All
input/output lines remain unchanged.
The MCU can be brought out of the stop mode only by:
• An IRQ external interrupt
• Port A external interrupt, if selected as a mask option
• An externally generated reset
When exiting stop mode, the internal oscillator resumes after a 4064
PH2 clock cycle oscillator stabilization delay.
NOTE:
Execution of the STOP instruction without conversion to halt (via mask
option) causes the oscillator to stop, and therefore disable the COP
watchdog timer. If the COP watchdog timer is to be used, stop mode
should be changed to halt mode by selecting the appropriate mask
option.
Technical Data
Operating Modes
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MC68HC05P18A