MC68HC908AP16CFB datasheet(230/440 Pages) MOTOROLA

230 / 440 page

Serial Communications Interface

Data Sheet

MC68HC908AP Family — Rev. 2.5

230

MOTOROLA

13.5 Low-Power Modes

The WAIT and STOP instructions put the MCU in low power-

consumption standby modes.

13.5.1 Wait Mode

The SCI module remains active after the execution of a WAIT

instruction. In wait mode, the SCI module registers are not accessible by

the CPU. 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.

Refer to 9.6 Low-Power Modes for information on exiting wait mode.

13.5.2 Stop Mode

The SCI module is inactive after the execution of a STOP instruction.

The STOP instruction does not affect SCI register states. SCI module

operation resumes after an external interrupt.

Because the internal clock is inactive during stop mode, entering stop

mode during an SCI transmission or reception results in invalid data.

Refer to 9.6 Low-Power Modes for information on exiting stop mode.

13.6 SCI During Break Module Interrupts

The system integration module (SIM) controls whether status bits in

other modules can be cleared during the break state. The BCFE bit in

the SIM break flag control register (SBFCR) enables software to clear

status bits during the break state.

To allow software to clear status bits during a break interrupt, write a

logic 1 to the BCFE bit. If a status bit is cleared during the break state, it

remains cleared when the MCU exits the break state.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MC68HC908AP16CFB Datasheet(PDF) 230 Page - Motorola, Inc