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CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
μ
PD78018FY SUBSERIES)
16.1 Functions of Serial Interface Channel 0
Serial interface channel 0 has the following four modes:
Table 16-2. Differences in Modes of Serial Interface Channel 0
Caution
Do not change the operation mode (3-wire serial I/O, 2-wire serial I/O, or I
2
C bus) while the
operation of serial interface channel 0 is enabled. To change the operation mode, stop the serial
operation.
Operation
Mode
Pins Used
Operation
stop mode
–
3-wire
serial I/O
mode
SCK0 (serial clock),
SO0 (serial output),
SI0 (serial input)
2-wire
serial I/O
mode
SCK0 (serial clock),
SB0 or SB1 (serial
data bus)
I
2
C
bus mode SDA0 or SDA1
(serial data bus)
SCL (serial clock),
Features
Mode used when no serial transfer is performed
Power consumption can be reduced
Short data transfer processing time because
independent input and output lines are used,
allowing simultaneous tranmission and reception.
MSB/LSB selectable for first bit of 8-bit data by serial
transfer
Any data transfer format can be supported by the
program and lines for lhand-shake conventionally
necessary for connecting multiple devices can be
eliminated
Supports I
2
C bus format
Because serial bus consists of two signal lines,
number of ports can be reduced and wiring distance
on PWB can be shortened even when plural micro-
computers are connected.
Applications
–
Useful for connecting
peripheral I/Os and
display controllers
with conventional
clocked serial
interface such as 75X/
XL series, 78K series,
and 17K series
Useful for connecting
CPU and peripheral
IC containing
serial interface
conforming to I
2
C bus