Renesas RL78 Series User Manual page 575

RL78/G1D
14.5.13 Wakeup function
2
The I C bus slave function is a function that generates an interrupt request signal (INTIICAn) when a local address and
extension code have been received.
This function makes processing more efficient by preventing unnecessary INTIICAn signal from occurring when
addresses do not match.
When a start condition is detected, wakeup standby mode is set. This wakeup standby mode is in effect while
addresses are transmitted due to the possibility that an arbitration loss may change the master device (which has
generated a start condition) to a slave device.
To use the wakeup function in the STOP mode, set the WUPn bit to 1. Addresses can be received regardless of the
operation clock. An interrupt request signal (INTIICAn) is also generated when a local address and extension code have
been received. Operation returns to normal operation by using an instruction to clear (0) the WUPn bit after this interrupt
has been generated.
Figure 14-22 shows the flow for setting WUPn = 1 and Figure 14-23 shows the flow for setting WUPn = 0 upon an
address match.
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
Figure 14-22. Flow When Setting WUPn = 1
START
MSTSn = STDn = EXCn = COIn =0?
Yes
WUPn = 1
Wait
STOP instruction execution
Remark n = 0
CHAPTER 14 SERIAL INTERFACE IICA
No
Waits for three cycles of f .
MCK
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