MC68HC908GR16 Datasheet, PDF (119/310 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Low-Power Modes
Computer Operating Properly Module (COP)
10.5.2 Stop Mode
If the OSCSTOPEN bit in the CONFIG register is cleared (default), then the STOP
instruction disables the CGM (oscillator and phase-locked loop) and holds low all
CGM outputs (CGMXCLK, CGMOUT, and CGMINT).
If the STOP instruction is executed with the VCO clock, CGMVCLK, divided by two
driving CGMOUT, the PLL automatically clears the BCS bit in the PLL control
register (PCTL), thereby selecting the crystal clock, CGMXCLK, divided by two as
the source of CGMOUT. When the MCU recovers from STOP, the crystal clock
divided by two drives CGMOUT and BCS remains clear.
If the OSCSTOPEN bit in the CONFIG register is set, then the phase locked loop
is shut off, but the oscillator will continue to operate in stop mode.
10.6 Computer Operating Properly Module (COP)
10.6.1 Wait Mode
The COP remains active during wait mode. If COP is enabled, a reset will occur at
COP timeout.
10.6.2 Stop Mode
Stop mode turns off the COPCLK input to the COP and clears the COP prescaler.
Service the COP immediately before entering or after exiting stop mode to ensure
a full COP timeout period after entering or exiting stop mode.
The STOP bit in the CONFIG1 register enables the STOP instruction. To prevent
inadvertently turning off the COP with a STOP instruction, disable the STOP
instruction by clearing the STOP bit.
10.7 External Interrupt Module (IRQ)
10.7.1 Wait Mode
The external interrupt (IRQ) module remains active in wait mode. Clearing the
IMASK1 bit in the IRQ status and control register enables IRQ CPU interrupt
requests to bring the MCU out of wait mode.
10.7.2 Stop Mode
The IRQ module remains active in stop mode. Clearing the IMASK1 bit in the IRQ
status and control register enables IRQ CPU interrupt requests to bring the MCU
out of stop mode.
MC68HC908GR16 — Rev. 1.0
MOTOROLA
Low-Power Modes
For More Information On This Product,
Go to: www.freescale.com
Data Sheet
119