mc68hc908ap8a Freescale Semiconductor, Inc, mc68hc908ap8a Datasheet - Page 174

• Manufacturer Part Number: mc68hc908ap8a
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface Module (SCI)
11.8.7 SCI Baud Rate Register
The baud rate register (SCBR) selects the baud rate for both the receiver and the transmitter.
SCP1 and SCP0 — SCI Baud Rate Prescaler Bits
SCR2–SCR0 — SCI Baud Rate Select Bits
Use this formula to calculate the SCI baud rate:
where:
174
These read/write bits select the baud rate prescaler divisor as shown in
and SCP0.
These read/write bits select the SCI baud rate divisor as shown in
SCR2–SCR0.
SCI clock source = f
(selected by SCIBDSRC bit in CONFIG2 register)
PD = prescaler divisor
BD = baud rate divisor
Address:
Reset:
Read:
Write:
$0019
BUS
0
0
SCR2, SCR1, and SCR0
SCP1 and SCP0
or CGMXCLK
Figure 11-16. SCI Baud Rate Register (SCBR)
= Unimplemented
00
01
10
11
Table 11-6. SCI Baud Rate Prescaling
baud rate
Table 11-7. SCI Baud Rate Selection
MC68HC908AP A-Family Data Sheet, Rev. 3
6
0
0
000
001
010
011
100
101
110
111
SCP1
=
5
0
SCI clock source
-------------------------------------------- -
64 PD BD
×
SCP0
4
0
×
Prescaler Divisor (PD)
Baud Rate Divisor (BD)
R
R
3
0
13
1
3
4
= Reserved
128
SCR2
16
32
64
1
2
4
8
2
0
Table
Table
11-7. Reset clears
SCR1
1
0
11-6. Reset clears SCP1
Freescale Semiconductor
SCR0
Bit 0
0