CHAPTER 17 SERIAL INTERFACE IIC0 (
µ
PD780344Y, 780354Y SUBSERIES ONLY)
350
User’s Manual U15798EJ2V0UD
Figure 17-18. Communication Reservation Protocol
Note
The communication reservation operation executes a write to IIC shift register 0 (IIC0) when a stop condition
interrupt request occurs.
Remark
STT0:
Bit 1 of IIC control register 0 (IICC0)
MSTS0: Bit 7 of IIC status register 0 (IICS0)
IIC0:
IIC shift register 0
17.5.15 Other cautions
After a reset, when changing from a mode in which no stop condition has been detected (the bus has not been
released) to a master device communication mode, first generate a stop condition to release the bus, then perform
master device communication.
When using multiple masters, it is not possible to perform master device communication when the bus has not
been released (when a stop condition has not been detected).
Use the following sequence for generating a stop condition.
(a) Set IIC transfer clock select register 0 (IICCL0).
(b) Set bit 7 (IICE0) of IIC control register 0 (IICC0).
(c) Set bit 0 (SPT0) of IICC0.
DI
SET1 STT0
Define communication
reservation
Wait
Cancel communication
reservation
No
Yes
MOV IIC0, #
××
H
EI
MSTS0 = 0?
(Communication reservation)
Note
(Generate start condition)
Sets STT0 flag (communication reservation)
Gets wait period set by software (see
Table 17-5
).
Confirmation of communication reservation
Clear user flag
IIC0 write operation
Defines that communication reservation is in effect
(defines and sets user flag to any part of RAM)
Содержание mPD780344 Series
Страница 2: ...2 User s Manual U15798EJ2V0UD MEMO...