CHAPTER 17 SERIAL INTERFACE IIC0
Preliminary User’s Manual U17260EJ3V1UD
421
(4) IIC clock selection register 0 (IICCL0)
This register is used to set the transfer clock for the I
2
C bus.
IICCL0 is set by a 1-bit or 8-bit memory manipulation instruction. However, the CLD0 and DAD0 bits are read-
only. The SMC0, CL01, and CL00 bits are set in combination with bit 0 (CLX0) of IIC function expansion
register 0 (IICX0) (see
17.3 (6) I
2
C transfer clock setting method
).
Set IICCL0 while bit 7 (IICE0) of IIC control register 0 (IICC0) is 0.
Reset signal generation sets IICCL0 to 00H.
Figure 17-8. Format of IIC Clock Selection Register 0 (IICCL0)
Address: FFA8H
After reset: 00H
R/W
Note
Symbol 7
6 <5> <4> <3> <2> 1
0
IICCL0 0
0 CLD0
DAD0
SMC0
DFC0
CL01
CL00
CLD0
Detection of SCL0 pin level (valid only when IICE0 = 1)
0
The SCL0 pin was detected at low level.
1
The SCL0 pin was detected at high level.
Condition for clearing (CLD0 = 0)
Condition for setting (CLD0 = 1)
•
When the SCL0 pin is at low level
•
When IICE0 = 0 (operation stop)
•
Reset
•
When the SCL0 pin is at high level
DAD0
Detection of SDA0 pin level (valid only when IICE0 = 1)
0
The SDA0 pin was detected at low level.
1
The SDA0 pin was detected at high level.
Condition for clearing (DAD0 = 0)
Condition for setting (DAD0 = 1)
•
When the SDA0 pin is at low level
•
When IICE0 = 0 (operation stop)
•
Reset
•
When the SDA0 pin is at high level
SMC0 Operation
mode
switching
0
Operates in standard mode.
1
Operates in high-speed mode.
DFC0
Digital filter operation control
0
Digital filter off.
1
Digital filter on.
Digital filter can be used only in high-speed mode.
In high-speed mode, the transfer clock does not vary regardless of DFC0 bit set (1)/clear (0).
The digital filter is used for noise elimination in high-speed mode.
Note
Bits 4 and 5 are read-only.
Remark
IICE0: Bit 7 of IIC control register 0 (IICC0)