MC908KX2MDWE Datasheet, PDF (134/210 Pages) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

Serial Communications Interface Module (SCI)
SCP1 and SCP0 — SCI Baud Rate Prescaler Bits
These read/write bits select the baud rate prescaler divisor as shown in Table 12-6. Reset clears SCP1
and SCP0.
Table 12-6. SCI Baud Rate Prescaling
SCP[1:0]
00
01
10
11
Prescaler Divisor (PD)
1
3
4
13
SCR2–SCR0 — SCI Baud Rate Select Bits
These read/write bits select the SCI baud rate divisor as shown in Table 12-7. Reset clears
SCR2–SCR0.
Table 12-7. SCI Baud Rate Selection
SCR[2:1:0]
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 = _{6----f4--B---×}-A---P-U----DD----C--_×---L-B--K---D---
where:
f_BAUDCLK = baud clock frequency
PD = prescaler divisor
BD = baud rate divisor
Table 12-8 shows the SCI baud rates that can be generated with a 4.9152-MHz CGMXCLK frequency.
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
134
Freescale Semiconductor