MC68HC908GZ8 Datasheet, PDF (45/344 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Low-Power Modes
Enhanced Serial Communications Interface Module (ESCI)
3.11 Enhanced Serial Communications Interface Module (ESCI)
3.11.1 Wait Mode
The enhanced serial communications interface (ESCI), or SCI module for short,
module remains active in wait mode. Any enabled CPU interrupt request from the
SCI module can bring the MCU out of wait mode.
If SCI module functions are not required during wait mode, reduce power
consumption by disabling the module before executing the WAIT instruction.
3.11.2 Stop Mode
The SCI module is inactive in stop mode. The STOP instruction does not affect SCI
register states. SCI module operation resumes after the MCU exits stop mode.
Because the internal clock is inactive during stop mode, entering stop mode during
an SCI transmission or reception results in invalid data.
3.12 Serial Peripheral Interface Module (SPI)
3.12.1 Wait Mode
The serial peripheral interface (SPI) module remains active in wait mode. Any
enabled CPU interrupt request from the SPI module can bring the MCU out of wait
mode.
If SPI module functions are not required during wait mode, reduce power
consumption by disabling the SPI module before executing the WAIT instruction.
3.12.2 Stop Mode
The SPI module is inactive in stop mode. The STOP instruction does not affect SPI
register states. SPI operation resumes after an external interrupt. If stop mode is
exited by reset, any transfer in progress is aborted, and the SPI is reset.
3.13 Timebase Module (TBM)
3.13.1 Wait Mode
The timebase module (TBM) remains active after execution of the WAIT
instruction. In wait mode, the timebase register is not accessible by the CPU.
If the timebase functions are not required during wait mode, reduce the power
consumption by stopping the timebase before enabling the WAIT instruction.
MC68HC908GZ8
MOTOROLA
Low-Power Modes
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Data Sheet
45