mc68hc908ap8a Freescale Semiconductor, Inc, mc68hc908ap8a Datasheet - Page 153

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

11.4 Functional Description
Figure 11-2
communication among the MCU and remote devices, including other MCUs. The transmitter and receiver
of the SCI operate independently, although they use the same baud rate generator. During normal
operation, the CPU monitors the status of the SCI, writes the data to be transmitted, and processes
received data.
The baud rate clock source for the SCI can be selected via the configuration bit, SCIBDSRC, of the
CONFIG2 register ($001D).
Freescale Semiconductor
CGMXCLK
CGMXCLK is from CGM module
IT12 = f
IT12
RxD
SL = 0 => X = A
SL = 1 => X = B
BUS
shows the structure of the SCI module. The SCI allows full-duplex, asynchronous, NRZ serial
SCRIE
SCTIE
TCIE
RWU
SCIBDSRC
SBK
ILIE
RE
TE
CONFIG
A
B
FROM
SL
SHIFT REGISTER
X
REGISTER
SCI DATA
RECEIVE
÷ 4
CONTROL
WAKEUP
SCTE
SCRF
IDLE
SCALER
Figure 11-2. SCI Module Block Diagram
TC
ENSCI
PRE-
MC68HC908AP A-Family Data Sheet, Rev. 3
DIVIDER
BAUD
÷ 16
CONTROL
RECEIVE
INTERNAL BUS
LOOPS
BKF
RPF
DATA SELECTION
CONTROL
OR
NF
PE
FE
FLAG
CONTROL
WAKE
ILTY
PEN
PTY
LOOPS
ENSCI
M
TRANSMIT
CONTROL
SHIFT REGISTER
DMARE
DMATE
TXINV
ORIE
NEIE
PEIE
FEIE
R8
T8
REGISTER
TRANSMIT
SCI DATA
Functional Description
TxD
153