MC908KX2MDWE Datasheet, PDF (115/210 Pages) Freescale Semiconductor, Inc – High-performance M68HC08 architecture, Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

Functional Description
Addr.
$0013
$0014
$0015
$0016
$0017
$0018
$0019
Register Name
SCI Control Register 1 ^Read:
(SCC1) Write:
See page 125. _Reset:
SCI Control Register 2 ^Read:
(SCC2) Write:
See page 127. _Reset:
SCI Control Register 3 ^Read:
(SCC3) Write:
See page 129. _Reset:
SCI Status Register 1 ^Read:
(SCS1) Write:
See page 130. _Reset:
SCI Status Register 2 ^Read:
(SCS2) Write:
See page 132. _Reset:
SCI Data Register ^Read:
(SCDR) Write:
See page 133. _Reset:
SCI Baud Rate Register ^Read:
(SCBR) Write:
See page 133. _Reset:
Bit 7
LOOPS
0
SCTIE
0
R8
U
SCTE
1
0
0
R7
T7
0
0
6
ENSCI
0
TCIE
0
T8
U
TC
5
TXINV
0
SCRIE
0
R
0
SCRF
1
0
0
0
0
0
R6
R5
T6
T5
0
SCP1
0
0
= Unimplemented
4
3
M
WAKE
0
0
ILIE
TE
0
0
R
ORIE
0
0
IDLE
OR
0
0
0
0
0
0
R4
R3
T4
T3
Unaffected by reset
SCP0
R
0
0
R = Reserved
Figure 12-4. SCI I/O Register Summary
2
ILTY
0
RE
0
NEIE
0
NF
0
0
0
R2
T2
SCR2
0
1
Bit 0
PEN
PTY
0
0
RWU
SBK
0
0
FEIE
PEIE
0
0
FE
PE
0
0
BKF
RPF
0
0
R1
R0
T1
T0
SCR1
SCR0
0
0
U = Unaffected
12.4.2 Transmitter
Figure 12-5 shows the structure of the SCI transmitter.
12.4.2.1 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).
12.4.2.2 Character Transmission
During an SCI transmission, the transmit shift register shifts a character out to the TxD pin. The SCI data
register (SCDR) is the write-only buffer between the internal data bus and the transmit shift register. To
initiate an SCI transmission:
1. Enable the SCI by writing a 1 to the enable SCI bit (ENSCI) in SCI control register 1 (SCC1).
2. Enable the transmitter by writing a 1 to the transmitter enable bit (TE) in SCI control register 2
(SCC2).
3. Clear the SCI transmitter empty bit by first reading SCI status register 1 (SCS1) and then writing
to the SCDR.
4. Repeat step 3 for each subsequent transmission.
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
Freescale Semiconductor
115