
162/189
SERIAL COMMUNICATIONS INTERFACE (SCI)
REGISTER DESCRIPTION (Cont’d)
Bit 2 = INPEN:
All Input Disable.
0: Enable SIN/RXCLK/DCD inputs.
1: Disable SIN/RXCLK/DCD inputs.
Bit 1:0 = “Don't Care”
SYNCHRONOUS OUTPUT CONTROL (SOCR)
R255 - Read/Write
Reset value: 0000 0001 (01h)
Bit 7 = OUTPL:
SOUT Output Polarity.
0: Polarity not inverted.
1: Polarity inverted.
Note: OUTPL only affects the data sent by the
transmitter section. In Auto-Echo mode SOUT =
SIN even if OUTPL=1. In Loop-Back mode, the
state of OUTPL is irrelevant.
Bit 6 = OUTSB:
SOUT Output Stand-By Level.
0: SOUT stand-by level is HIGH.
1: SOUT stand-by level is LOW.
Bit 5 = OCKPL:
Transmitter Clock Polarity.
0: CLKOUT is active on the rising edge.
1: CLKOUT is active on the falling edge.
Note: OCKPL only affects the transmitter clock. In
Auto-Echo mode CLKOUT = RXCLK independ-
ently of the state of OCKPL. In Loop-Back mode
the state of OCKPL is irrelevant.
Bit 4 = OCKSB:
Transmitter Clock Stand-By Lev-
el.
0: The CLKOUT stand-by level is HIGH.
1: The CLKOUT stand-by level is LOW.
Bit 3 = RTSEN:
RTS and SDS Output Enable.
0: Disable the RTS and SDS hardware synchroni-
sation.
1: Enable the RTS and SDS hardware synchroni-
sation.
Notes:
– When RTSEN is set, the RTS output becomes
active just before the first active edge of CLK-
OUT and indicates to target device that the MCU
is about to send a synchronous frame; it returns
to its stand-by value just after the last active edge
of CLKOUT (MSB transmitted).
– When RTSEN is set, the SDS output becomes
active high and indicates to the target device that
the MCU is about to send the first bit of a syn-
chronous frame on the Serial Output Pin
(SOUT); it returns to low level as soon as the
second bit is sent on the Serial Output Pin
(SOUT). In this way a positive pulse is generated
each time that the first bit of a synchronous frame
is present on the Serial Output Pin (SOUT).
Bit 2 = RTSPL:
RTS Output Polarity.
0: The RTS output is active when LOW.
1: The RTS output is active when HIGH.
Note: RTSPL only affects the RTS activity on the
output pin. In Auto-Echo mode RTS = DCD inde-
pendently from the RTSPL value. In Loop-Back
mode RTSPL value is 'Don't Care'.
Bit 1 = Reserved.
Bit 0 = “Don't Care”
n
70
OUTP
L
OUTS
B
OCKP
L
OCKS
B
RTSE
N
RTS
PL
-X
9