Datasheet
V850ES/JG3 CHAPTER 17 I
2
C BUS
R01UH0015EJ0300 Rev.3.00 Page 596 of 870
Sep 30, 2010
17.15 Cautions
(1) When IICFn.STCENn bit = 0
Immediately after the I
2
C0n operation is enabled, the bus communication status (IICFn.IICBSYn bit = 1) is
recognized regardless of the actual bus status. To execute master communication in the status where a stop
condition has not been detected, generate a stop condition and then release the bus before starting the master
communication.
Use the following sequence for generating a stop condition.
<1> Set the IICCLn register.
<2> Set the IICCn.IICEn bit.
<3> Set the IICCn.SPTn bit.
(2) When IICFn.STCENn bit = 1
Immediately after I
2
C0n operation is enabled, the bus released status (IICBSYn bit = 0) is recognized regardless of
the actual bus status. To generate the first start condition (IICCn.STTn bit = 1), it is necessary to confirm that the
bus has been released, so as to not disturb other communications.
(3) When the IICCn.IICEn bit of the V850ES/JG3 is set to 1 while communications among other devices are in
progress, the start condition may be detected depending on the status of the communication line. Be sure to set
the IICCn.IICEn bit to 1 when the SCL0n and SDA0n lines are high level.
(4) Determine the operation clock frequency by the IICCLn, IICXn, and OCKSm registers before enabling the operation
(IICCn.IICEn bit = 1). To change the operation clock frequency, clear the IICCn.IICEn bit to 0 once.
(5) After the IICCn.STTn and IICCn.SPTn bits have been set to 1, they must not be re-set without being cleared to 0
first.
(6) If transmission has been reserved, set the IICCN.SPIEn bit to 1 so that an interrupt request is generated by the detection
of a stop condition. After an interrupt request has been generated, the wait state will be released by writing
communication data to I
2
Cn, then transferring will begin. If an interrupt is not generated by the detection of a stop
condition, transmission will halt in the wait state because an interrupt request was not generated. However, it is not
necessary to set the SPIEn bit to 1 for the software to detect the IICSn.MSTSn bit.
Remark n = 0 to 2
m = 0, 1