Wait - NEC 78K0 Series User Manual

17.5.6 Wait

The 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 SCL0 pin to low level notifies the communication partner of the wait state. When wait state has been
canceled for both the master and slave devices, the next data transfer can begin.
(1) When master device has a nine-clock wait and slave device has an eight-clock wait
(master transmits, slave receives, and ACKE0 = 1)
Master
IIC0
SCL0
Slave
IIC0
SCL0
ACKE0
Transfer lines
SCL0
SDA0
430
CHAPTER 17 SERIAL INTERFACE IIC0
Figure 17-18. Wait (1/2)
Master returns to high
impedance but slave
is in wait state (low level).
6 7 8 9
Wait after output
of eighth clock
H
Wait from slave
6 7 8
D2 D1 D0
Preliminary User's Manual U17260EJ3V1UD
Wait after output
of ninth clock
IIC0 data write (cancel wait)
1
FFH is written to IIC0 or WREL0 is set to 1
Wait from master
9 1
ACK D7
2 3
2 3
D6 D5