Freescale Semiconductor MC68HC908MR32 - Manual (Page 178)

Serial Communications Interface Module (SCI)
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
178 Freescale Semiconductor
SCR2–SCR0 — SCI Baud Rate Select Bits
These read/write bits select the SCI baud rate divisor as shown in Table 13-6 . Reset clears
SCR2–SCR0.
Use this formula to calculate the SCI baud rate:
where:
f
OP
= internal operating frequency
PD = prescaler divisor
BD = baud rate divisor
Table 13-7 shows the SCI baud rates that can be generated with a 4.9152-MHz crystal with the CGM set
for an f
OP
of 7.3728 MHz and the CGM set for an f
OP
of 4.9152 MHz.
Table 13-6. SCI Baud Rate Selection
SCR2:SCR1:SCR0 Baud Rate Divisor (BD)
000 1
001 2
010 4
011 8
100 16
101 32
110 64
111 128
Baud rate
fOP
64 PD BD
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