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CHAPTER 16 SERIAL INTERFACE IICA
User’s Manual U19780EJ2V0UD
437
Figure 16-7. Format of IICA Flag Register 0 (IICAF0)
<7>
STCF
Condition for clearing (STCF = 0)
•
Cleared by STT0 = 1
•
When IICE0 = 0 (operation stop)
•
Reset
Condition for setting (STCF = 1)
•
Generating start condition unsuccessful and STT0
cleared to 0 when communication reservation is
disabled (IICRSV = 1).
STCF
0
1
Generate start condition
Start condition generation unsuccessful: clear STT0 flag
STT0 clear flag
IICAF0
Symbol
<6>
IICBSY
5
0
4
0
3
0
2
0
<1>
STCEN
<0>
IICRSV
Address: FFAAH After reset: 00H R/W
Note
Condition for clearing (IICBSY = 0)
•
Detection of stop condition
•
When IICE0 = 0 (operation stop)
•
Reset
Condition for setting (IICBSY = 1)
•
Detection of start condition
•
Setting of IICE0 when STCEN = 0
IICBSY
0
1
Bus release status (communication initial status when STCEN = 1)
Bus communication status (communication initial status when STCEN = 0)
I
2
C bus status flag
Condition for clearing (STCEN = 0)
•
Cleared by instruction
•
Detection of start condition
•
Reset
Condition for setting (STCEN = 1)
•
Set by instruction
STCEN
0
1
After operation is enabled (IICE0 = 1), enable generation of a start condition upon detection of
a stop condition.
After operation is enabled (IICE0 = 1), enable generation of a start condition without detecting
a stop condition.
Initial start enable trigger
Condition for clearing (IICRSV = 0)
•
Cleared by instruction
•
Reset
Condition for setting (IICRSV = 1)
•
Set by instruction
IICRSV
0
1
Enable communication reservation
Disable communication reservation
Communication reservation function disable bit
Note
Bits 6 and 7 are read-only.
Cautions 1. Write to STCEN only when the operation is stopped (IICE0 = 0).
2. As the bus release status (IICBSY = 0) is recognized regardless of the actual bus
status when STCEN = 1, when generating the first start condition (STT0 = 1), it is
necessary to verify that no third party communications are in progress in order to
prevent such communications from being destroyed.
3. Write to IICRSV only when the operation is stopped (IICE0 = 0).
Remark
STT0: Bit 1 of IICA control register 0 (IICACTL0)
IICE0: Bit 7 of IICA control register 0 (IICACTL0)