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CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ6V0UD
347
(3) IIC flag registers 0, 1 (IICF0, IICF1)
IICFn is used to set the I
2
Cn operation mode and to indicate the I
2
C bus status.
IICFn can be set by an 8-bit or 1-bit memory manipulation instruction.
The IICRSVn bit is used to enable/disable the communication reservation function (see
10.4.12
Communication reservation
).
The STCENn bit is used to set the initial value of the IICBSYn bit (see
10.4.13 Cautions
).
The IICRSVn and STCENn bits can be written only when the I
2
Cn operation is disabled (IICEn bit of IIC control
register n (IICCn) = 0). After operation is enabled, the IICFn register can be read (n = 0).
RESET input clears IICFn to 00H.
When IICFn = 00H, these registers operate in the same way as the A versions.
(1/2)
<7>
STCFn
Condition for clearing (STCFn = 0)
• Clearing by setting STTn = 1
• RESET input
Condition for setting (STCFn = 1)
• Clearing of STTn when communication reservation
is disabled (IICRSVn = 1).
STCFn
0
1
Generate start condition
Clear STTn bit
STTn bit clear
IICFn
(n = 0, 1)
<6>
IICBSYn
5
0
4
0
3
0
2
0
<1>
STCENn
<0>
IICRSVn
After reset: 00H R/W
Note
Address: FFFFF33CH, FFFFF33EH
Condition for clearing (IICBSYn = 0)
• Detection of stop condition
• RESET input
Setting conditions (IICBSYn = 1)
• Detection of start condition
• Setting of IICEn when STCENn = 0
IICBSYn
0
1
Bus release status
Bus communication status
I
2
Cn bus status
Note
Bits 6 and 7 are read-only bits.
Remark
STTn: Bit 1 of IIC control register n (IICCn)
IICEn: Bit 7 of IIC control register n (IICCn)