MC68HC05B6_13 Datasheet, PDF (93/302 Pages) Freescale Semiconductor, Inc – Microcontrollers

6.13
SCI during STOP mode
When the MCU enters STOP mode, the baud rate generator driving the receiver and transmitter
is shut down. This stops all SCI activity. Both the receiver and the transmitter are unable to
operate.
If the STOP instruction is executed during a transmitter transfer, that transfer is halted. When
STOP mode is exited as a result of an external interrupt, that particular transmission resumes.
If the receiver is receiving data when the STOP instruction is executed, received data sampling is
stopped (baud generator stops) and the rest of the data is lost.
Warning: For the above reasons, all SCI transactions should be in the idle state when the STOP
instruction is executed.
6
6.14
SCI during WAIT mode
The SCI system is not affected by WAIT mode and continues normal operation. Any valid SCI
interrupt will wake-up the system. If required, the SCI system can be disabled prior to entering
WAIT mode by writing a zero to the transmitter and receiver enable bits in the serial
communication control register 2 at $000F. This action will result in a reduction of power
consumption during WAIT mode.
MC68HC05B6
Rev. 4.1
SERIAL COMMUNICATIONS INTERFACE
Freescale
6-21