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CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
μ
PD78018FY SUBSERIES)
16.4 Operation of Serial Interface Channel 0
Serial interface channel 0 operates in the following four operation modes:
Operation stop mode
3-wire serial I/O mode
2-wire serial I/O mode
I
2
C (Inter IC) bus mode
16.4.1 Operation stop mode
Serial transfer is not executed in this mode. Consequently, the power consumption can be reduced. The serial
I/O shift register 0 (SIO0) can be used as an ordinary 8-bit register because it does not perform the shift operation.
In the operation stop mode, the P25/SIO/SB0/SDA0, P26/SO0/SB1/SDA1, and P27/SCK0/SCL pins can be used
as ordinary I/O port pins.
(1) Register setting
The operation stop mode is set by using the serial operation mode register 0 (CSIM0).
CSIM0 is set by using a 1-bit or 8-bit memory manipulation instruction.
This register is set to 00H when the RESET signal is input.
16.4.2 Operation in 3-wire serial I/O mode
This mode is useful for connecting peripheral I/Os and display controllers that have the conventional clocked serial
interface of the 75X/XL series, 78K series, and 17K series.
In this mode, communication is established by using three signal lines: serial clock (SCK0), serial output (SO0),
and serial input (SI0).
(1) Register setting
The 3-wire serial I/O mode is set by using the serial operation mode register 0 (CSIM0) and serial bus interface
control register (SBIC).
(a) Serial operation mode register 0 (CSIM0)
CSIM0 is set by a 1-bit or 8-bit memory manipulation instruction.
This register is set to 00H when the RESET signal is input.
4
3
2
Symbol
1
0
FF60H
CSIM00
CSIM0
CSIM01
CSIM03 CSIM02
CSIM04
WUP
COI
CSIE0
Address
On reset
R/W
00H
R/W
R/W
CSIE0
0
1
Serial interface channel 0 operation control
Stops operation
Enables operation
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