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CHAPTER 16 SERIAL INTERFACE IICA
User’s Manual U19780EJ2V0UD
450
Figure 16-19. Wait (2/2)
(2) When master and slave devices both have a nine-clock wait
(master transmits, slave receives, and ACKE0 = 1)
Master
IICA
SCAL0
Slave
IICA
SCLA0
ACKE0
Transfer lines
SCLA0
SDAA0
H
6
7
8
9
1
2
3
Master and slave both wait
after output of ninth clock
Wait from
master and
slave
Wait from slave
IICA data write (cancel wait)
FFH is written to IICA or WREL0 is set to 1
6
7
8
9
1
2
3
D2
D1
D0
ACK
D7
D6
D5
Generate according to previously set ACKE0 value
Remark
ACKE0: Bit 2 of IICA control register 0 (IICACTL0)
WREL0: Bit 5 of IICA control register 0 (IICACTL0)
A wait may be automatically generated depending on the setting of bit 3 (WTIM0) of IICA control register 0
(IICACTL0).
Normally, the receiving side cancels the wait state when bit 5 (WREL0) of IICACTL0 is set to 1 or when FFH is
written to the IICA shift register (IICA), and the transmitting side cancels the wait state when data is written to IICA.
The master device can also cancel the wait state via either of the following methods.
• By setting bit 1 (STT0) of IICACTL0 to 1
• By setting bit 0 (SPT0) of IICACTL0 to 1