340
CHAPTER 18 I
2
C BUS MODE (
µ
PD784225Y SUBSERIES ONLY)
User’s Manual U12697EJ3V0UM
Figure 18-17 shows the communication reservation procedure.
Figure 18-17. Communication Reservation Procedure
Note
When the communication is being reserved, serial shift register 0 (IIC0) is written by the stop condition
interrupt.
Remark
STT0:
Bit 1 in I
2
C bus control register 0 (IICC0)
MSTS0: Bit 7 in I
2
C bus status register 0 (IICS0)
IIC0:
Serial shift register 0
DI
SET1 STT0
Define communication
reservation.
Communication
reservation is released.
MOV IIC0, #
××
H
EI
Wait
MSTS0 = 0 ?
; Set the STT0 flag (communication reservation).
; Define that communication is being reserved.
(Defines and sets the user flag to any RAM.)
; Clear the user flag.
; IIC0 write
; Save the wait time by the software
(see
Table 18-5
).
; Check the communication reservation.
Yes
(Communication reservation)
Note
No
(Start condition generated)