MC68HC908GP20 Datasheet, PDF (285/406 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Table 18-7. 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--^B----^U---^S---------------
64 × PD × BD
where:
f_BUS = bus frequency
PD = prescaler divisor
BD = baud rate divisor
SCI_BDSRC is an input to the SCI. Normally it will be tied off low at the
top level to select the bus clock as the clock source. This makes the
formula:
baud rate = ------------f--^B----^U---^S---------------
64 × PD × BD
Table 18-8 shows the SCI baud rates that can be generated with a
4.9152-MHz bus clock.
MC68HC908GP20 — Rev 2.1
Freescale Semiconductor
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