Datasheet
15.2.3 SCI Control Register 1 (SCIx_C1)
This read/write register controls various optional features of the SCI system.
Address: Base address + 2h offset
Bit 7 6 5 4 3 2 1 0
Read
LOOPS SCISWAI RSRC M WAKE ILT PE PT
Write
Reset
0 0 0 0 0 0 0 0
SCIx_C1 field descriptions
Field Description
7
LOOPS
Loop Mode Select
Selects between loop back modes and normal 2-pin full-duplex modes. When LOOPS is set, the
transmitter output is internally connected to the receiver input.
0 Normal operation - RxD and TxD use separate pins.
1 Loop mode or single-wire mode where transmitter outputs are internally connected to receiver input.
(See RSRC bit.) RxD pin is not used by SCI.
6
SCISWAI
SCI Stops in Wait Mode
0 SCI clocks continue to run in wait mode so the SCI can be the source of an interrupt that wakes up the
CPU.
1 SCI clocks freeze while CPU is in wait mode.
5
RSRC
Receiver Source Select
This bit has no meaning or effect unless the LOOPS bit is set to 1. When LOOPS is set, the receiver input
is internally connected to the TxD pin and RSRC determines whether this connection is also connected to
the transmitter output.
0 Provided LOOPS is set, RSRC is cleared, selects internal loop back mode and the SCI does not use
the RxD pins.
1 Single-wire SCI mode where the TxD pin is connected to the transmitter output and receiver input.
4
M
9-Bit or 8-Bit Mode Select
0 Normal - start + 8 data bits (lsb first) + stop.
1 Receiver and transmitter use 9-bit data characters start + 8 data bits (lsb first) + 9th data bit + stop.
3
WAKE
Receiver Wakeup Method Select
0 Idle-line wakeup.
1 Address-mark wakeup.
2
ILT
Idle Line Type Select
Setting this bit to 1 ensures that the stop bits and logic 1 bits at the end of a character do not count toward
the 10 or 11 bit times of logic high level needed by the idle line detection logic.
0 Idle character bit count starts after start bit.
1 Idle character bit count starts after stop bit.
Table continues on the next page...
Register definition
MC9S08PA60 Reference Manual, Rev. 1, 9/2012
408 Freescale Semiconductor, Inc.