Freescale Semiconductor MC68HC908MR32 - Manual (Page 159)

Functional Description
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor 159
13.3 Functional Description
Figure 13-2 shows the structure of the SCI module. The SCI allows full-duplex, asynchronous, NRZ serial
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.
Figure 13-2. SCI Module Block Diagram
SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
SCTIE
TCIE
SCRIE
ILIE
TE
RE
RWU
SBK
R8
T8
ORIE
FEIE
PEIE
BKF
RPF
SCI DATA
RECEIVE
SHIFT REGISTER
SCI DATA
REGISTER
TRANSMIT
SHIFT REGISTER
NEIE
M
WAKE
ILTY
FLAG
CONTROL
TRANSMIT
CONTROL
RECEIVE
CONTROL
DATA SELECTION
CONTROL
WAKEUP
PTY
PEN
REGISTER
TRANSMITTER
INT
E
RRUPT
CONT
ROL
R
ECEIV
E
R
INT
E
RRUPT
CONT
ROL
E
RROR
INT
E
RRUPT
CONT
ROL
CONTROL
ENSCI
LOOPS
ENSCI
PTF4/RxD PTF5/TxD
INTERNAL BUS
TXINV
LOOPS
ч 4
ч 16
PRE-
SCALER
BAUD RATE
GENERATOR
f OP