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CHAPTER 15 SERIAL INTERFACE CHANNEL 0 (
μ
PD78018F SUBSERIES)
15.4.2 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.
Notes 1.
Bit 6 (COI) is a read-only bit.
2.
This pin can be used as P25 (CMOS input) when used only for transfer.
3.
Be sure to set WUP to 0 in the 3-wire serial I/O mode.
Remark
×
PM
××
: Port mode register
P
××
: Output latch of port
: Don’t care
<6>
<5>
4
3
2
1
0
<7>
Symbol
CSIM0 CSIE0
COI
WUP
CSIM04 CSIM03 CSIM02 CSIM01 CSIM00
CSIM01
0
1
Selects clock of serial interface channel 0
Clock externally input to SCK0 pin
Output of 8-bit timer register 2 (TM2)
0
R/W
1
Clock specified by bits 0-3 of timer clock select register 3 (TCL3)
CSIM
04
0
CSIM00
×
0
1
FF60H 00H R/W
Note 1
Address On reset R/W
R/W
CSIM
03
CSIM
02
PM25 P25 PM26 P26 PM27 P27
Operation
mode
First bit
SI0/SB0/P25
pin function
SO0/SB1/P26
pin function
SCK0/P27
pin function
×
WUP
0
1
Controls wake-up function
Note 3
Generates interrupt request signal in all modes each time serial transfer is executed
Generates interrupt request signal when address received after bus has been released in SBI mode (when
CMDD = RELD = 1) coincides with data of slave address register (SVA)
R/W
CSIE0
0
Controls operation of serial interface channel 0
Stops operation
Enables operation
R/W
1
1
MSB
LSB
×
0
0
0
1
3-wire serial
l/O mode
SI0
(input)
SO0
(CMOS output)
SCK0
(CMOS l/O)
Note 2
SBI mode (Refer to
15.4.3 Operation in SBI mode
.)
1
0
2-wire serial I/O mode (Refer to
15.4.4 Operation in 2-wire serial I/O mode
.)
1
1
1