MC68HC08AZ16 Datasheet, PDF (189/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Serial Communications Interface Module (SCI)
SCI during break module interrupts
The system integration module (SIM) controls whether status bits in other
modules can be cleared during interrupts generated by the break
module. The BCFE bit in the SIM break flag control register (SBFCR)
enables software to clear status bits during the break state. See SIM
break flag control register (SBFCR) on page 93.
To allow software to clear status bits during a break interrupt, write a ’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.
To protect status bits during the break state, write a ’0’ to the BCFE bit.
With BCFE at 0 0 0 (its default state), software can read and write I/O
registers during the break state without affecting status bits. Some status
bits have a two-step read/write clearing procedure. If software does the
first step on such a bit before the break, the bit cannot change during the
break state as long as BCFE is at ’0’. After the break, doing the second
step clears the status bit.
MC68HC08AZ32
188
Serial Communications Interface Module (SCI)
20-sci
MOTOROLA