NXP Semiconductors MC9S08QL4, Справочное руководство

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Serial Communications Interface (S08SCIV4)
MC9S08QL8 MCU Series Reference Manual, Rev. 1
NXP Semiconductors 187
14.2.2 SCI Control Register 1 (SCIC1)
This read/write register is used to control various optional features of the SCI system.
Table 14-2. SCIBDL Field Descriptions
Field Description
7:0
SBR[7:0]
Baud Rate Modulo Divisor — These 13 bits in SBR[12:0] are referred to collectively as BR, and they set the
modulo divide rate for the SCI baud rate generator. When BR = 0, the SCI baud rate generator is disabled to
reduce supply current. When BR = 1 to 8191, the SCI baud rate = BUSCLK/(16

BR). See also BR bits in
Table 14-1 .
7 6 5 4 3 2 1 0
R
LOOPS SCISWAI RSRC M WAKE ILT PE PT
W
Reset 0 0 0 0 0 0 0 0
Figure 14-6. SCI Control Register 1 (SCIC1)
Table 14-3. SCIC1 Field Descriptions
Field Description
7
LOOPS
Loop Mode Select — Selects between loop back modes and normal 2-pin full-duplex modes. When LOOPS = 1,
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 = 1, 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 = 1, RSRC = 0 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 — Refer to Section 14.3.3.2, Receiver Wakeup Operation for more
information.
0 Idle-line wakeup.
1 Address-mark wakeup.
2
ILT
Idle Line Type Select — Setting this bit to 1 ensures that the stop bit 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. Refer to
Section 14.3.3.2.1, Idle-Line Wakeup for more information.
0 Idle character bit count starts after start bit.
1 Idle character bit count starts after stop bit.