MC68HC08AS32A Datasheet, PDF (197/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
I/O Registers
SCR2–SCR0 — SCI Baud Rate Select Bits
These read/write bits select the SCI baud rate divisor as shown in Table 13-7.
Reset clears SCR2–SCR0.
Table 13-7. SCI Baud Rate Selection
SCR2, SCR1, and SCR0
000
001
010
011
100
101
110
111
Baud Rate Divisor (BD)
1
2
4
8
16
32
64
128
Use this formula to calculate the SCI baud rate:
Baud rate =
f_xclk
64 x PD x BD
where:
f_xclk = crystal frequency
PD = prescaler divisor
BD = baud rate divisor
Table 13-8 shows the SCI baud rates that can be generated with a 4.9152-MHz
bus clock when f_BUS is selected as SCI clock source.
MC68HC08AS32A — Rev. 1
MOTOROLA
Serial Communications Interface (SCI)
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Data Sheet
197