Datasheet
V850ES/JG3-H, V850ES/JH3-H CHAPTER 19 I
2
C BUS
R01UH0042EJ0500 Rev.5.00 Page 876 of 1513
Aug 12, 2011
19.15 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 release 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-H and V850ES/JH3-H is set to 1 while other devices are
communicating, 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 using the IICCLn, IICXn, and OCKSm registers before enabling the
operation (IICCn.IICEn bit = 1). To change the operation clock frequency, first clear the IICCn.IICEn bit to 0.
(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 status will be released by
writing communication data to I
2
Cn, then transfer will begin. If an interrupt is not generated by the detection of a
stop condition, transmission will halt in the wait status 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