
MC68CK338
MC68CK338TS/D
MOTOROLA
75
M — Mode Select
0 = SCI frame: one start bit, eight data bits, one stop bit (10 bits total)
1 = SCI frame: one start bit, nine data bits, one stop bit (11 bits total)
WAKE — Wakeup by Address Mark
0 = SCI receiver awakened by idle-line detection
1 = SCI receiver awakened by address mark (last bit set)
TIE — Transmit Interrupt Enable
0 = SCI TDRE interrupts inhibited
1 = SCI TDRE interrupts enabled
TCIE — Transmit Complete Interrupt Enable
0 = SCI TC interrupts inhibited
1 = SCI TC interrupts enabled
RIE — Receiver Interrupt Enable
0 = SCI RDRF interrupt inhibited
1 = SCI RDRF interrupt enabled
ILIE — Idle-Line Interrupt Enable
0 = SCI IDLE interrupts inhibited
1 = SCI IDLE interrupts enabled
TE — Transmitter Enable
0 = SCI transmitter disabled (TXD pin may be used as I/O)
1 = SCI transmitter enabled (TXD pin dedicated to SCI transmitter)
The transmitter retains control of the TXD pin until completion of any character transfer that was in
progress when TE is cleared.
RE — Receiver Enable
0 = SCI receiver disabled (status bits inhibited)
1 = SCI receiver enabled
RWU — Receiver Wakeup
0 = Normal receiver operation (received data recognized)
1 = Wakeup mode enabled (received data ignored until awakened)
Setting RWU enables the wakeup function, which allows the SCI to ignore received data until awakened
by either an idle line or address mark (as determined by WAKE). When in wakeup mode, the receiver
status flags are not set, and interrupts are inhibited. This bit is cleared automatically (returned to normal
mode) when the receiver is awakened.
SBK — Send Break
0 = Normal operation
1 = Break frame(s) transmitted after completion of current frame
SBK provides the ability to transmit a break code from the SCI. If the SCI is transmitting when SBK is
set, it will transmit continuous frames of zeros after it completes the current frame, until SBK is cleared.
If SBK is toggled (one to zero in less than one frame interval), the transmitter sends only one or two
break frames before reverting to idle line or beginning to send data.
SCSR —
SCI Status Register
$YFFC0C
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NOT USED
TDRE
TC
RDRF
RAF
IDLE
OR
NF
FE
PF
RESET:
1
1
0
0
0
0
0
0
0