Motorola MC68HC908AB32 - SCI Baud Rate Selection

Serial Communications Interface
Technical Data MC68HC908AB32 — Rev. 1.0
276 Serial Communications Interface Module (SCI) MOTOROLA
Use this formula to calculate the SCI baud rate:
where:
SCI clock source = CGMXCLK
(See 9.5.6 Crystal Output Frequency Signal (CGMXCLK).)
PD = prescaler divisor
BD = baud rate divisor
This makes the formula:
Table 15-8 shows the SCI baud rates that can be generated with a
4.9152MHz CGMXCLK.
Table 15-7. SCI Baud Rate Selection
SCR2, SCR1, and SCR0
Baud Rate
Divisor (BD)
000 1
001 2
010 4
011 8
100 16
101 32
110 64
111 128
baud rate
SCI clock source
64 PD BD××
---------------------------------------------=
baud rate
CGMXCLK
64 PD BD××
------------------------------------=