NEC 78K0 Series User Manual page 438

Program processing
Hardware processing
SCL0
1 2 3
SDA0
Remark IIC0:
STT0:
STD0: Bit 1 of IIC status register 0 (IICS0)
SPD0: Bit 0 of IIC status register 0 (IICS0)
Communication reservations are accepted via the following timing. After bit 1 (STD0) of IIC status register 0
(IICS0) is set to 1, a communication reservation can be made by setting bit 1 (STT0) of IIC control register 0
(IICC0) to 1 before a stop condition is detected.
Figure 17-21. Timing for Accepting Communication Reservations
SCL0
SDA0
STD0
SPD0
Figure 17-22 shows the communication reservation protocol.
438
CHAPTER 17 SERIAL INTERFACE IIC0
Figure 17-20. Communication Reservation Timing
STT0 = 1
Communi-
cation
reservation
4 5 6 7
Generate by master device with bus mastership
IIC shift register 0
Bit 1 of IIC control register 0 (IICC0)
Standby mode
Preliminary User's Manual U17260EJ3V1UD
Write to
IIC0
Set SPD0
Set
and
STD0
INTIIC0
8 9 1 2 3 4 5 6