CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
260
Figure 10-9. IIC Control Register n (IICCn) (3/4)
After reset: 00H
R/W
Address: FFFFF340H, FFFFF350H
<7>
<6>
<5>
<4>
<3>
<2>
<1>
<0>
IICCn
IICEn
LRELn
WRELn
SPIEn
WTIMn
ACKEn
STTn
SPTn
(n = 0, 1)
ACKEn
Acknowledge control
0
Disable acknowledge.
1
Enable acknowledge. During the ninth clock period, the SDA line is set to low level. However, the ACK is
invalid during address transfers and is valid when EXCn = 1.
Condition for clearing (ACKEn = 0)
Note
Condition for setting (ACKEn = 1)
•
Cleared by instruction
•
When RESET is input
•
Set by instruction
STTn
Start condition trigger
0
Does not generate a start condition.
1
When bus is released (in STOP mode):
Generates a start condition (for starting as master). The SDAn line is changed from high level to low level
and then the start condition is generated. Next, after the rated amount of time has elapsed, SCLn is
changed to low level.
When bus is not used:
This trigger functions as a start condition reserve flag. When set, it releases the bus and then
automatically generates a start condition.
In the wait state (when master device)
Generates a restart condition after releasing the wait.
Cautions concerning set timing
•
For master reception:
Cannot be set during transfer. Can be set only when ACKEn has been set to 0 and slave
has been notified of final reception.
•
For master transmission: A start condition cannot be generated normally during the ACKn period. Set during the wait
period.
•
Cannot be set at the same time as SPTn
Condition for clearing (STTn = 0)
Condition for setting (STTn = 1)
•
Cleared by instruction
•
Cleared by loss in arbitration
•
Cleared after start condition is generated by master
device
•
When LRELn = 1
•
When IICEn = 0
•
Cleared when RESET is input
•
Set by instruction
Note
This flag’s signal is invalid when IICEn = 0.
Remark
Bit 1 (STTn) is 0 if it is read immediately after data setting.
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