CHAPTER 17 SERIAL INTERFACE IIC0
Preliminary User’s Manual U17260EJ3V1UD
420
Figure 17-7. Format of IIC Flag Register 0 (IICF0)
<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
IICF0
Symbol
<6>
IICBSY
5
0
4
0
3
0
2
0
<1>
STCEN
<0>
IICRSV
Address: FFABH 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 STCEN0 = 1)
Bus communication status (communication initial status when STCEN0 = 0)
I
2
C bus status flag
Condition for clearing (STCEN = 0)
•
Detection of stop 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 IIC control register 0 (IICC0)
IICE0: Bit 7 of IIC control register 0 (IICC0)