Serial Communications Interface Module (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 13-6.
Reset clears SCR2–SCR0.
Table 13-6. SCI Baud Rate Selection
SCR2:SCR1:SCR0
Baud Rate Divisor (BD)
000
001
010
011
100
101
110
111
1
2
4
8
16
32
64
128
Use this formula to calculate the SCI baud rate:
f
OP
Baud rate = ------------------------------------
64 × PD × BD
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 fOP of 7.3728 MHz and the CGM set for an fOP of
4.9152 MHz.
MC68HC908MR32 • MC68HC908MR16 — Rev. 6.0
MOTOROLA Serial Communications Interface Module (SCI)
Data Sheet
193
FREESCALE [ Freescale ]
