
319
CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
m
PD78064Y Subseries)
(3) Register setting
The I
2
C mode setting is performed by the serial operating mode register 0 (CSIM0), the serial bus interface
control register (SBIC), and the interrupt timing specify register (SINT).
(a) Serial operating mode register 0 (CSIM0)
CSIM0 is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets 00H.
The CSIM0 format is shown below, where the bits used in the I
2
C bus mode are shaded.
R/W
CSIM01
0
1
1
CSIM00
x
0
1
Serial Interface Channel 0 Clock Selection
Input clock from off-chip to SCL pin
8-bit timer register 2 (TM2) output
Note 2
Clock specified with bits 0 to 3 of timer clock select register 3 (TCL3)
R/W
CSIM CSIM
04
0
1
CSIM
02
3-wire serial I/O mode (see section 16.4.2 "3-wire serial I/O mode operation")
0
x
x
0
0
0
1
Note3
Note3
PM25 P25
PM26 P26
PM27 P27
Operation
mode
Start
bit
SI0/SB0/SDA0/
P25 pin function
SO0/SB1/SDA1/
P26 pin function
SCK0/SCL/P27
pin function
03
x
1
2-wire
serial I/O or
I
2
C bus mode
2-wire
serial I/O or
I
2
C bus mode
MSB
P25
(CMOS I/O)
SB1/SDA1
(N-ch open-
drain I/O)
P26
(CMOS I/O)
SCK0/SCL
(N-ch open-
drain I/O)
SCK0/SCL
(N-ch open-
drain I/O)
1
1
1
0
0
x
Note3 Note3
x
0
1
MSB
SB0/SDA0
(N-ch open-
drain I/O)
R/W
WUP
0
1
Wake-up Function Control
Interrupt request signal generation with each serial transfer in any mode
In I
2
C bus mode, interrupt request signal is generated when the address data received after start condition
detection (when CMDD = 1) matches data in slave address register.
R
COI
0
1
Slave Address Comparison Result Flag
Note 4
Slave address register not equal to data in serial I/O shift register 0
Slave address register equal to data in serial I/O shift register 0
R/W
CSIE0
0
1
Serial Interface Channel 0 Operation Control
Stops operation.
Enables operation.
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.
Can be used freely as a port.
4.
When CSIE0 = 0, COI is 0.
Remark:
x: Don’t care
6
5
4
3
2
1
0
7
Symbol
CSIM0
Address After Reset R/W
CSIE0
COI
WUP
CSIM04 CSIM03 CSIM02 CSIM01 CSIM00
FF60H 00H R/W
Note 1