Serial Communication Interface (SCI)
MCF51CN128 Reference Manual, Rev. 6
Freescale Semiconductor
13-4
13.1.4
Block Diagram
shows the transmitter portion of the SCI.
Figure 13-2. SCI Transmitter Block Diagram
H
8
7
6
5
4
3
2
1
0
L
SCID – Tx Buffer
(Write-Only)
Internal Bus
St
op
11-BIT Transmit Shift Register
St
ar
t
SHIFT DIRECTION
ls
b
1
×
Baud
Rate Clock
Parity
Generation
Transmit Control
Shift Enab
le
Pream
b
le (All 1s)
Break (All 0
s
)
SCI Controls TxD
TxD Direction
TO TxD
Pin Logic
Loop
Control
To Receive
Data In
To TxD Pin
Tx Interrupt
Request
Load F
rom SC
IxD
