CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
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Wait signal (WAIT)
The wait signal (WAIT) is used to notify the communication partner that a device (master or slave) is preparing
to transmit or receive data (i.e., is in a wait state).
Setting the SCLn pin to low level notifies the communication partner of the wait status. When wait status has
been canceled for both the master and slave devices, the next data transfer can begin (n = 0, 1).
Figure 10-23. Wait Signal (1/2)
(a) When master device has a nine-clock wait and slave device has an eight-clock wait
(master: transmission, slave: reception, and ACKEn = 1)
SCL
6
SDA
7
8
9
1
2
3
SCL
IIC0
6
H
7
8
1
2
3
D2
D1
D0
ACK
D7
D6
D5
9
IIC0
SCL
ACKE
Master
Master returns to high
impedance but slave
is in wait state (low level).
Wait after output
of ninth clock.
IIC0 data write (cancel wait)
Slave
Wait after output
of eighth clock.
FFH is written to IIC0 or WREL is set to 1.
Transfer lines
Remark
n = 0, 1