SH7708 Datasheet, PDF (363/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

1 3 . 2 . 8 Serial Port Register (SCSPTR)
The serial port register (SCSPTR) is an 8-bit register that the CPU can always read and write. It
controls I/O and data of the port multiplexed with the serial communications interface (SCI) pins.
Input data can be read from the RxD pin and output data can be transmitted to the TxD pin; this
controls breaks for serial transmission and reception.
SCSPTR is initialized to H'00 by a power-on reset. It is not initialized by a manual reset or in
standby mode.
Bit: 7
6
5
4
3
2
1
0
Bit name: —
—
—
— SPB1IO SPB1DT SPB0IO SPB0DT
Initial value: 0
0
0
0
0
—
0
—
R/W: R
R
R
R
R/W R/W R/W R/W
Bits 7 to 4—Reserved: These bits always read 0. The write value should always be 0.
Bit 3—Serial Port Clock Port I/O (SPB1IO): Specifies serial port SCK pin input/output. When
the SCK pin is actually set as a port output pin and outputs the value set by the SPB1DT bit, the
C/A bit in SCSMR and the CKE1 and CKE0 bits in SCSCR should be cleared to 0.
Bit 3: SPB1IO
0
1
Description
The SPB1DT value is not output to the SCK pin.
The SPB1DT bit value is output to the SCK pin.
(Initial value)
Bit 2—Serial Port Clock Port Data (SPB1DT): Specifies the serial port SCK pin input/output
data. Input or output is specified by the SPB1IO bit (see the description of SPB1IO for details).
When output is specified, the value of the SPB1DT bit is output to the SCK pin. The SCK pin
value is read from the SPB1DT bit regardless of the value of the SPB1IO bit. The initial value of
this bit after a power-on reset is undefined.
Bit 2: SPB1DT
0
1
Description
I/O data level is low.
I/O data level is high.
(Initial value)
Bit 1—Serial Port Break I/O (SPB0IO): Specifies the serial port TxD pin output condition. When
the TxD pin is actually set as a port output pin and outputs the value set by the SPB0DT bit, the
TE bit in SCSCR should be cleared to 0.
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