Datasheet

V850ES/JG3 CHAPTER 17 I
2
C BUS
R01UH0015EJ0300 Rev.3.00 Page 550 of 870
Sep 30, 2010
After reset: 00H R/W
Note
Address: IICF0 FFFFFD8AH, IICF1 FFFFFD9AH, IICF2 FFFFFDAAH
<7> <6> 5 4 3 2 <1> <0>
IICFn STCFn IICBSYn 0 0 0 0 STCENn IICRSVn
(n = 0 to 2)
STCFn STTn bit clear
0 Start condition issued
1 Start condition cannot be issued, STTn bit cleared
Condition for clearing (STCFn bit = 0) Condition for setting (STCFn bit = 1)
• Cleared by IICCn.STTn bit = 1
• When the IICCn.IICEn bit = 0
• After reset
• When start condition is not issued and STTn flag is
cleared to 0 during communication reservation is
disabled (IICRSVn bit = 1).
IICBSYn I
2
C0n bus status
0 Bus released status (default communication status when STCENn bit = 1)
1 Bus communication status (default communication status when STCENn bit = 0)
Condition for clearing (IICBSYn bit = 0) Condition for setting (IICBSYn bit = 1)
• When stop condition is detected
• When the IICEn bit = 0
• After reset
• When start condition is detected
• By setting the IICEn bit when the STCENn bit = 0
STCENn Initial start enable trigger
0 Start conditions cannot be generated until a stop condition is detected following operation enable
(IICEn bit = 1).
1 Start conditions can be generated even if a stop condition is not detected following operation enable
(IICEn bit = 1).
Condition for clearing (STCENn bit = 0) Condition for setting (STCENn bit = 1)
• When start condition is detected
• After reset
• Setting by instruction
IICRSVn Communication reservation function disable bit
0 Communication reservation enabled
1 Communication reservation disabled
Condition for clearing (IICRSVn bit = 0)
Condition for setting (IICRSVn bit = 1)
• Clearing by instruction
• After reset
• Setting by instruction
Note Bits 6 and 7 are read-only bits.
Cautions 1. Write the STCENn bit only when operation is stopped (IICEn bit = 0).
2. When the STCENn bit = 1, the bus released status (IICBSYn bit = 0) is recognized
regardless of the actual bus status immediately after the I
2
Cn bus operation is enabled.
Therefore, to issue the first start condition (STTn bit = 1), it is necessary to confirm
that the bus has been released, so as to not disturb other communications.
3. Write the IICRSVn bit only when operation is stopped (IICEn bit = 0).