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CHAPTER 17 SERIAL INTERFACE CHANNEL 0 (
µ
PD78054Y Subseries)
(3) Register setting
The I
2
C mode is set with 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.
R/W
CSIM01 CSIM00
Serial Interface Channel 0 Clock Selection
0 × Input clock from off-chip to SCL pin
1 0 8-bit timer register 2 (TM2) output (See
Note 2
)
1 1 Clock specified with bits 0 to 3 of timer clock select register 3 (TCL3)
R/W
CSIM CSIM CSIM PM25 P25 PM26 P26 PM27 P27
Operation Start
SI0/SB0/SDA0/
SO0/SB1/SDA1/
SCK0/SCL/P27
04 03 02 mode bit
P25 pin function
P26 pin function
pin function
0 × 3-wire serial I/O mode (see section 17.4.2 "Operation in 3-wire serial I/O mode")
11 0××0 0 0 1 2-wire MSB P25 SB1/SDA1 SCK0/SCL
Note 3 Note 3
serial I/O or (CMOS I/O) N-ch open- N-ch open-
I
2
C bus mode drain I/O drain I/O
11 100××0 1 2-wire MSB SB0/SDA0 P26 SCK0/SCL
Note 3 Note 3
serial I/O or N-ch open- (CMOS I/O) N-ch open-
I
2
C bus mode drain I/O drain I/O
R/W WUP Wake-up Function Control
Note 4
0 Interrupt request signal generation with each serial transfer in any mode
1 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 (SVA).
R COI Slave Address Comparison Result Flag (See
Note 5
)
0 Slave address register (SVA) not equal to data in serial I/O shift register 0 (SIO0)
1 Slave address register (SVA) equal to data in serial I/O shift register 0 (SIO0)
R/W CSIE0 Serial Interface Channel 0 Operation Control
0 Stops operation.
1 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. To use the wake-up function (WUP = 1), set the bit 5 (SIC) of the interrupt timing specify register (SINT)
to 1. Do not execute an instruction that writes the serial I/O shift register 0 (SIO0) while WUP = 1.
5. When CSIE0 = 0, COI is 0.
Remark × : Don’t care
PM×× : Port mode register
P×× : Port output latch
<6><5>43210<7>
Symbol
CSIM0
FF60H 00H R/W
Note1
Address After Reset R/W
CSIE0 COI WUP
CSIM04 CSIM03 CSIM02 CSIM01 CSIM00