MC68HC908GR8 Datasheet, PDF (168/286 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Serial Communications Interface (SCI)
INTERNAL BUS
SCIBDSRC
FROM
CONFIG2
CGMXCLK
IT12
A
B
SL
X
SL = 0 => X = A
SL = 1 => X = B
SCP1
SCP0
÷4
PRE- BAUD
SCALER DIVIDER
SCR1
SCR2
SCR0
÷ 16
PE1/RxD
BKF
RPF
DATA
RECOVERY
ALL 0s
SCI DATA REGISTER
11-BIT
RECEIVE SHIFT REGISTER
H876543210L
M
WAKE
ILTY
PEN
PTY
WAKEUP
LOGIC
PARITY
CHECKING
IDLE
ILIE
DMARE
SCRF
SCRIE
DMARE
SCRF
SCRIE
DMARE
OR
ORIE
NF
NEIE
FE
FEIE
PE
PEIE
SCRF
IDLE
R8
ILIE
SCRIE
DMARE
OR
ORIE
NF
NEIE
FE
FEIE
PE
PEIE
RWU
Figure 18-5. SCI Receiver Block Diagram
18.4.3.1 Character Length
The receiver can accommodate either 8-bit or 9-bit data. The state of the M bit in SCI control register 1
(SCC1) determines character length. When receiving 9-bit data, bit R8 in SCI control register 3 (SCC3)
is the ninth bit (bit 8). When receiving 8-bit data, bit R8 is a copy of the eighth bit (bit 7).
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
168
Freescale Semiconductor