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CHAPTER 11 SERIAL INTERFACE FUNCTION
User’s Manual U15109EJ3V0UD
421
(2) When communication reservation function is disabled (IICRSVn of IICFn register = 1)
When the STTn bit of the IICCn register is set when the bus is not used in a communication during bus
communication, this request is rejected and a start condition is not generated. The following two statuses are
included in the status where bus is not used.
•
When arbitration results in neither master nor slave operation
•
When an extension code is received and slave operation is disabled (ACK is not returned and the bus was
released when LRELn of IIC control register n (IICCn) was set to 1) (n = 0, 1).
To confirm whether the start condition was generated or request was rejected, check the STCFn flag of the IICFn
register. The time shown in Table 11-11 is required until the STCFn flag is set after setting STTn = 1. Therefore,
secure the time by software.
Table 11-11. Wait Time
IICCEn1
IICCEn0
CLn1
CLn0
Wait Time
×
×
0
0
3 clocks
×
×
0
1
3 clocks
×
×
1
0
6 clocks
0
0
1
1
3
×
N
0
1
1
1
6 clocks
1
0
1
1
9 clocks
Remarks
1.
N: TM5 and TM6 outputs
×
: don’t care
2.
n = 0, 1
Caution
If the slave status is entered by an address match or expansion code reception (timing
shown in Figure 11-35), do not set STTn to 1. When set, the communication reservation
status is entered.
Figure 11-35. STTn = 1 Setting Disabled Timing
Remark
n = 0, 1
SDAn
AD6 AD5 AD4 AD3 AD2 AD1 AD0
D7 D6 D5
D2 D1 D0 ACK
R/W ACK
SCLn
IICBSYn
When COIn = 1 or EXCn = 1,
setting STTn = 1 is disabled
Start condition
Stop condition
Rising edge of
8th address clock