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CHAPTER 15 SERIAL INTERFACE CHANNEL 0 (
μ
PD78018F SUBSERIES)
15.1 Functions of Serial Interface Channel 0
Serial interface channel 0 has the following four modes:
Table 15-2. Differences in Modes of Serial Interface Channel 0
Operation
Mode
Pins Used
Operation
stop mode
–
3-wire
serial I/O
mode
SCK0 (serial clock),
SO0 (serial output),
SI0 (serial input)
SBI mode SCK0 (serial clock),
SB0 or SB1 (serial
data bus)
2-wire
serial I/O
mode
SCK0 (serial clock),
SB0 or SB1 (serial
data bus)
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 transmission and reception.
MSB/LSB selectable for first bit of 8-bit data by
serial transfer.
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 microcomputers are connected.
High-speed serial interface conforming to NEC’s
standard bus format.
Serial bus has address, command, data informa-
tion.
Wake-up function for hand-shake, output function
of acknowledge and busy signals available.
Any data transfer format can be supported by the
program and lines for hand-shake conventionally
necessary for connecting multiple devices can be
eliminated.
Applications
–
Useful for connect-
ing peripheral I/Os
and display control-
lers with conven-
tional clocked serial
interface such as
75X/XL series, 78K
series, and 17K
series
Caution
Do not change the operation mode (3-wire serial I/O, 2-wire serial I/O, or SBI) while the operation
of serial interface channel 0 is enabled. To change the operation mode, stop the serial operation.