Functional Description and Application Information
Serial Communication Interface (S08SCIV4)
MM912F634
Freescale Semiconductor
112
4.15.2
Register Definition
The SCI has eight 8-bit registers to control baud rate, select SCI options, report SCI status, and for transmit/receive data.
This section refers to registers and control bits only by their names.
4.15.2.1
SCI Baud Rate Registers (SCIBD (hi), SCIBD (lo))
This pair of registers controls the prescale divisor for SCI baud rate generation. To update the 13-bit baud rate setting
[SBR12:SBR0], first write to SCIBD (hi) to buffer the high half of the new value, and then write to SCIBD (lo). The working value
in SCIBD (hi) does not change until SCIBD (lo) is written.
SCIBDL is reset to a non-zero value, so after reset the baud rate generator remains disabled until the first time the receiver or
transmitter is enabled (RE or TE bits in SCIC2 are written to 1).
Table 124. SCI Baud Rate Register (SCIBD (hi))
Access: User read/write
76
543
210
R
LBKDIE
RXEDGIE
0
SBR12
SBR11
SBR10
SBR9
SBR8
W
Reset
0
000
00
Note:
99. Offset related to 0x0200 for blocking access and 0x300 for non blocking access within the global address space.
Table 125. SCIBD (hi) Field Descriptions
Field
Description
7
LBKDIE
LIN Break Detect Interrupt Enable (for LBKDIF)
0 Hardware interrupts from LBKDIF disabled (use polling).
1 Hardware interrupt requested when LBKDIF flag is 1.
6
RXEDGIE
RxD Input Active Edge Interrupt Enable (for RXEDGIF)
0 Hardware interrupts from RXEDGIF disabled (use polling).
1 Hardware interrupt requested when RXEDGIF flag is 1.
4:0
SBR[128]
Baud Rate Modulo Divisor — The 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
Table 126. SCI Baud Rate Register (SCIBDL)
Access: User read/write
76
543
210
R
SBR7
SBR6
SBR5
SBR4
SBR3
SBR2
SBR1
SBR0
W
Reset
0
000
01
00
Note:
100. Offset related to 0x0200 for blocking access and 0x300 for non blocking access within the global address space.
Table 127. 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