CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
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(2) IIC status registers 0, 1 (IICS0, IICS1)
IICSn indicates the status of the I
2
Cn bus.
IICSn can be set by an 8-/1-bit memory manipulation instruction. IICSn is a read-only register (n = 0, 1).
RESET input sets IICSn to 00H.
Figure 10-10. IIC Status Register n (IICSn) (1/3)
After reset: 00H
R
Address: FFFFF342H, FFFFF352H
<7>
<6>
<5>
<4>
<3>
<2>
<1>
<0>
IICSn
MSTSn
ALDn
EXCn
COIn
TRCn
ACKDn
STDn
SPDn
(n = 0, 1)
MSTSn
Master device status
0
Slave device status or communication standby status
1
Master device communication status
Condition for clearing (MSTSn = 0)
Condition for setting (MSTSn = 1)
•
When a stop condition is detected
•
When ALDn = 1
•
Cleared by LRELn = 1
•
When IICEn changes from 1 to 0
•
When RESET is input
•
When a start condition is generated
ALDn
Detection of arbitration loss
0
This status means either that there was no arbitration or that the arbitration result was a “win”.
1
This status indicates the arbitration result was a “loss”. MSTSn is cleared.
Condition for clearing (ALDn = 0)
Condition for setting (ALDn = 1)
•
Automatically cleared after IICSn is read
Note
•
When IICEn changes from 1 to 0
•
When RESET is input
•
When the arbitration result is a “loss”.
Note
This register is also cleared when a bit manipulation instruction is executed for bits other than IICSn.
Remark
LRELn: Bit 6 of IIC control register n (IICCn)
IICEn:
Bit 7 of IIC control register n (IICCn)