Renesas RL78 Series User Manual page 551

RL78/G1D
Notes
STTn
1, 2
0 Do not generate a start condition.
1 When bus is released (in standby state, when IICBSYn = 0):
When a third party is communicating:
In the wait state (when master device):
Cautions concerning set timing
● For master reception:
● For master transmission: A start condition cannot be generated normally during the acknowledge period. Set to 1
● Cannot be set to 1 at the same time as stop condition trigger (SPTn).
● Once STTn is set (1), setting it again (1) before the clear condition is met is not allowed.
Condition for clearing (STTn = 0)
● Cleared by setting the STTn bit to 1 while
communication reservation is prohibited.
● Cleared by loss in arbitration
● Cleared after start condition is generated by master
device
● Cleared by LRELn = 1 (exit from communications)
● When IICEn = 0 (operation stop)
● Reset
Notes 1. The signal of this bit is invalid while IICEn is 0.
2. The STTn bit is always read as 0.
Remarks 1. IICRSVn:
2. n = 0
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
Figure 14-6. Format of IICA Control Register n0 (IICCTLn0) (3/4)
If this bit is set (1), a start condition is generated (startup as the master).
● When communication reservation function is enabled (IICRSVn = 0)
Functions as the start condition reservation flag. When set to 1, automatically generates a start
condition after the bus is released.
● When communication reservation function is disabled (IICRSVn = 1)
Even if this bit is set (1), the STTn bit is cleared and the STTn clear flag (STCFn) is set (1). No start
condition is generated.
Generates a restart condition after releasing the wait.
Cannot be set to 1 during transfer. Can be set to 1 only in the waiting period when the
ACKEn bit has been cleared to 0 and slave has been notified of final reception.
during the wait period that follows output of the ninth clock.
Bit 0 of IIC flag register n (IICFn)
STCFn: Bit 7 of IIC flag register n (IICFn)
CHAPTER 14 SERIAL INTERFACE IICA
Start condition trigger
Condition for setting (STTn = 1)
● Set by instruction
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