RL78/F13, F14 CHAPTER 16 SERIAL INTERFACE IICA
R01UH0368EJ0210 Rev.2.10 1051
Dec 10, 2015
16.5.13 Wakeup function
The I
2
C bus slave function is a function that generates an interrupt request signal (INTIICA0) when a local address and
extension code have been received.
This function makes processing more efficient by preventing unnecessary INTIICA0 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 WUP0 bit to 1. Addresses can be received regardless of the
operation clock. An interrupt request signal (INTIICA0) 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 WUP0 bit after this interrupt
has been generated.
Figure 16-23 shows the flow for setting WUP0 = 1 and Figure 16-24 shows the flow for setting WUP0 = 0 upon an address
match.
Figure 16-23. Flow When Setting WUP0 = 1
Wait for three cycles of the operation clock (f
MCK
)
Yes
No
START
WUP0 = 1
Wait
STOP instruction execution
MSTS0 = STD0 = EXC0 = COI0 =0?
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