Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
SCI I/O Registers
SCR2–SCR0 — SCI Baud Rate Select Bits
These read/write bits select the SCI baud rate, as shown in
Table 10-2. Reset has no effect on the SCR2–SCR0 bits.
Table 10-2. Baud Rate Selection
SCR[2:1:0]
000
SCI Baud Rate (Baud)
Prescaled clock ÷ 1
Prescaled clock ÷ 2
Prescaled clock ÷ 4
Prescaled clock ÷ 8
Prescaled clock ÷ 16
Prescaled clock ÷ 32
Prescaled clock ÷ 64
Prescaled clock ÷ 128
001
010
011
100
101
110
111
Table 10-3 shows all possible SCI baud rates derived from crystal
frequencies of 2 MHz, 4 MHz, and 4.194304 MHz.
MC68HC705C8A — Rev. 3
MOTOROLA
Technical Data
Serial Communications Interface (SCI)
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