Chapter 11 Serial Communications Interface (S08SCIV4)
MC9S08LG32 MCU Series, Rev. 5
Freescale Semiconductor
265
13.2.2
SCI Control Register 1 (SCIxC1)
This read/write register controls various optional features of the SCI system.
7
6
5
4
3
2
1
0
R
SBR[7:0]
W
Reset
0
0
0
0
0
1
0
0
Figure 13-5. SCI Baud Rate Register (SCIxBDL)
Table 13-3. SCIxBDL 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 is cleared, the SCI baud rate generator is disabled
to reduce supply current. When BR is 1 – 8191, the SCI baud rate equals BUSCLK/(16
×
BR). See also BR bits
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 13-6. SCI Control Register 1 (SCIxC1)
Table 13-4. SCIxC1 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
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.
Содержание MC9S08LG16
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Страница 26: ...Chapter 1 Device Overview MC9S08LG32 MCU Series Rev 5 26 Freescale Semiconductor...
Страница 40: ...Chapter 2 Pins and Connections MC9S08LG32 MCU Series Rev 5 40 Freescale Semiconductor...
Страница 96: ...Chapter 5 Resets Interrupts and General System Control MC9S08LG32 MCU Series Rev 5 96 Freescale Semiconductor...
Страница 296: ...Chapter 12 Serial Peripheral Interface S08SPIV4 MC9S08LG32 MCU Series Rev 5 296 Freescale Semiconductor...
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