165
CHAPTER 8 APPLICATIONS OF SERIAL INTERFACE
Figure 8-8. Format of Serial Operating Mode Register 0 (
μ
PD78018FY subseries) (1/2)
R/W
CSIM
CSIM
01
Selects clock of serial interface channel 0
00
0
×
Clock externally input to SCK0/SCL pin
1
0
Output of 8-bit timer register 2 (TM2)
Note 2
1
1
Clock specified by bits 0 through 3 of timer clock select register 3 (TCL3)
R/W
CSIMCSIM CSIM PM25 P25 PM26 P26
PM27
P27
Operating mode First bit
04
03
02
Function of
Function of
Function of
SI0/SB0/SDA0/P25 pin SO0/SB1/SDA1/P26 pinSCK0/SCL/P27
pin
0
×
0
1
×
0
0
0
1
3-wire serial
MSB
SI0
Note 3
SO0
SCK0
1
I/O mode
LSB
(input)
(CMOS output)
(CMOS I/O)
1
1
0
Note 4 Note 4
0
0
0
1
2-wire serial
I/O mode or
I
2
C bus mode
MSB
P25
(CMOS I/O)
SB1
(N-ch open drain (N-ch open drain
I/O)
SCK0/SCL
×
×
I/O)
1
0
0
Note 4 Note 4
0
1
SB0/SDA0
(N-ch open drain
(CMOS I/O)
I/O)
P26
×
×
R/W
WUP
Controls wake-up function
Note 5
0
Generates interrupt request signal in all modes each time serial transfer is executed
1
Generates interrupt request signal when address received after start condition has been detected (when CMDD
= 1) coincides with data of slave address register in I
2
C mode
Notes 1.
Bit 6 (COI) is a read-only bit.
2.
In the I
2
C bus mode, the clock frequency is 1/16 of the clock frequency output by TO2
3.
When only the transmission function is used, this pin can be used as P25 (CMOS I/O).
4.
These pins can be used as port pins.
5.
When using the wake-up function (WUP = 1), clear bit 5 (SIC) of the interrupt timing specification register
(SINT) to 0. While WUP = 1, do not execute an instruction that writes data to the I/O shift register 0
(SIO0).
Caution Do not change the operating mode (3-wire serial I/O/2-wire serial I/O/I
2
C bus) while the operation
of the serial interface channel 0 is enabled. To change the operating mode, stop the serial
operation.
Remark
×
: don’t care
PM
××
: Port mode register
P
××
: Output latch of port
7
CSIE
0
6
COI
5
WUP
4
CSIM
04
3
CSIM
03
2
CSIM
02
1
CSIM
01
0
CSIM
00
CSIM0
Symbol
FF60H
Address
At reset
R/W
00H
R/W
Note 1