Datasheet

Serial Communications Interface (SCI)
Functional Description
MC68HC908GR8 — Rev 4.0 Technical Data
MOTOROLA Serial Communications Interface (SCI) 237
Figure 18-4. SCI Transmitter
18.5.2.1 Character Length
The transmitter 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 transmitting 9-bit data, bit T8 in SCI control register 3 (SCC3) is
the ninth bit (bit 8).
DMATE
SCTE
PEN
PTY
H876543210L
11-BIT
TRANSMIT
STOP START
T8
DMATE
SCTE
SCTIE
TCIE
SBK
TC
PARITY
GENERATION
MSB
SCI DATA REGISTER
LOAD FROM SCDR SHIFT ENABLE
PREAMBLE
ALL 1s
BREAK
ALL 0s
TRANSMITTER
CONTROL LOGIC
SHIFT REGISTER
DMATE
TC
SCTIE
TCIE
SCTE
TRANSMITTER CPU INTERRUPT REQUEST
TRANSMITTER DMA SERVICE REQUEST
M
ENSCI
LOOPS
TE
PE2/TxD
TXINV
INTERNAL BUS
÷ 4
PRE-
SCALER
SCP1
SCP0
SCR2
SCR1
SCR0
BAUD
DIVIDER
÷ 16
SCTIE
CGMXCLK
IT12
A
B
SL
X
SL = 0 => X = A
SL = 1 => X = B
SCIBDSRC
FROM
CONFIG2
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
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