UPD78F1502AGK-GAK-AX Datasheet, PDF (608/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 15 SERIAL INTERFACE IICA
Figure 15-8. Format of IICA Flag Register (IICF)
Address: FFF52H After reset: 00H
Symbol <7>
<6>
5
IICF STCF IICBSY
0
R/W^Note
4
3
0
0
2
<1>
<0>
0
STCEN IICRSV
STCF
STT clear flag
0 Generate start condition
1 Start condition generation unsuccessful: clear STT flag
Condition for clearing (STCF = 0)
Condition for setting (STCF = 1)
• Cleared by STT = 1
• When IICE = 0 (operation stop)
• Reset
• Generating start condition unsuccessful and STT
cleared to 0 when communication reservation is
disabled (IICRSV = 1).
IICBSY
I²C bus status flag
0 Bus release status (communication initial status when STCEN = 1)
1 Bus communication status (communication initial status when STCEN = 0)
Condition for clearing (IICBSY = 0)
Condition for setting (IICBSY = 1)
• Detection of stop condition
• When IICE = 0 (operation stop)
• Reset
• Detection of start condition
• Setting of IICE when STCEN = 0
STCEN
Initial start enable trigger
0 After operation is enabled (IICE = 1), enable generation of a start condition upon detection of
a stop condition.
1 After operation is enabled (IICE = 1), enable generation of a start condition without detecting
a stop condition.
Condition for clearing (STCEN = 0)
Condition for setting (STCEN = 1)
• Cleared by instruction
• Detection of start condition
• Reset
• Set by instruction
IICRSV
Communication reservation function disable bit
0 Enable communication reservation
1 Disable communication reservation
Condition for clearing (IICRSV = 0)
Condition for setting (IICRSV = 1)
• Cleared by instruction
• Reset
• Set by instruction
Note Bits 6 and 7 are read-only.
Cautions 1. Write to STCEN only when the operation is stopped (IICE = 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 (STT = 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 (IICE = 0).
Remark STT: Bit 1 of IICA control register 0 (IICCTL0)
IICE: Bit 7 of IICA control register 0 (IICCTL0)
R01UH0004EJ0501 Rev.5.01
592
Jun 20, 2011