SH7708 Datasheet, PDF (437/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

15.2.3 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 communication 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. In addition, SCK pin data
reading and output data writing can be performed by means of bits 3 and 2.
All SCSPTR bits except bits 2 and 0 are initialized to 0 by a power-on reset; the value of bits
2 and 0 is undefined. SCSPTR is not initialized by a manual reset or in standby mode, and it
retains its contents.
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. (Initial value)
The SPB1DT bit value is output to the SCK pin.
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. (Initial value)
I/O data level is high.
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