MC68HC908AS32A Datasheet, PDF (168/280 Pages) Freescale Semiconductor, Inc – Microcontrollers

Serial Communications Interface (SCI)
14.4.1 Data Format
The SCI uses the standard non-return-to-zero mark/space data format illustrated in Figure 14-3.
8-BIT DATA FORMAT
PARITY
(BIT M IN SCC1 CLEAR)
OR DATA
BIT
NEXT
START
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 ^STOP BIT
BIT
9-BIT DATA FORMAT
(BIT M IN SCC1 SET)
NEXT
START
START
BIT BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 BIT 8 STOP BIT
BIT
Figure 14-3. SCI Data Formats
14.4.2 Transmitter
Figure 14-4 shows the structure of the SCI transmitter.
INTERNAL BUS
CGMXCLK
÷4
PRE- BAUD
SCALER DIVIDER
÷ 16
SCP1
SCP0
SCR2
SCR1
SCR0
TXINV
SCI DATA REGISTER
11-BIT
TRANSMIT
SHIFT REGISTER
H876543210L
M
PEN
PARITY
PTY
GENERATION
T8
TRANSMITTER CPU
INTERRUPT REQUEST
TRANSMITTER
CONTROL LOGIC
SCTE
SCTIE
TC
TCIE
SCTE
SCTIE
TC
TCIE
Figure 14-4. SCI Transmitter
SBK
LOOPS
ENSCI
TE
PTE0/TxD
MC68HC908AS32A Data Sheet, Rev. 2.0
168
Freescale Semiconductor