MC908AZ60ACFUER Datasheet, PDF (191/414 Pages) Freescale Semiconductor, Inc – To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to:

Low-Power Modes
• Noise flag (NF) — The NF bit is set when the SCI detects noise on incoming data or break
characters, including start, data, and stop bits. The noise error interrupt enable bit, NEIE, in SCC3
enables NF to generate SCI error CPU interrupt requests.
• Framing error (FE) — The FE bit in SCS1 is set when a logic 0 occurs where the receiver expects
a stop bit. The framing error interrupt enable bit, FEIE, in SCC3 enables FE to generate SCI error
CPU interrupt requests.
• Parity error (PE) — The PE bit in SCS1 is set when the SCI detects a parity error in incoming data.
The parity error interrupt enable bit, PEIE, in SCC3 enables PE to generate SCI error CPU interrupt
requests.
18.5 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
18.5.1 Wait Mode
The SCI 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.
18.5.2 Stop Mode
The SCI module is inactive in stop mode. The STOP instruction does not affect SCI register states. Any
enabled CPU interrupt request from the SCI module does not bring the MCU out of Stop mode. 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.
18.6 SCI During Break Module Interrupts
The BCFE bit in the break flag control register (BFCR) enables software to clear status bits during the
break state. (See Chapter 13 Break Module (BRK)).
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.
To protect status bits during the break state, write a logic 0 to the BCFE bit. With BCFE at logic 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 logic 0. After the
break, doing the second step clears the status bit.
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
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