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CHAPTER 16 SERIAL INTERFACE IICA
User’s Manual U19780EJ2V0UD
469
Figure 16-29. Master Operation in Multi-Master System (3/3)
Writing IICA
WTIM0 = 1
WREL0 = 1
Reading IICA
ACKE0 = 1
WTIM0 = 0
WTIM0 = WREL0 = 1
ACKE0 = 0
Writing IICA
Yes
TRC0 = 1?
Restart?
MSTS0 = 1?
Starts communication
(specifies an address and transfer direction).
Starts transmission.
No
Yes
Waits for data reception.
Starts reception.
Yes
No
INTIICA0
i
nterrupt occurs?
Yes
No
Transfer end?
Waits for detection of ACK.
Yes
No
INTIICA0
i
nterrupt occurs?
Waits for data transmission.
Does not participate
in communication.
Yes
No
INTIICA0
i
nterrupt occurs?
No
Yes
ACKD0 = 1?
No
Yes
No
C
2
Yes
MSTS0 = 1?
No
Yes
Transfer end?
No
Yes
ACKD0 = 1?
No
2
Yes
MSTS0 = 1?
No
2
Waits for detection of ACK.
Yes
No
INTIICA0
i
nterrupt occurs?
Yes
MSTS0 = 1?
No
C
2
Yes
EXC0 = 1 or COI0 = 1?
No
1
2
SPT0 = 1
STT0 = 1
Slave operation
END
Communication processing
Communication processing
Remarks 1.
Conform to the specifications of the product that is communicating, with respect to the transmission
and reception formats.
2.
To use the device as a master in a multi-master system, read the MSTS0 bit each time interrupt
INTIICA0 has occurred to check the arbitration result.
3.
To use the device as a slave in a multi-master system, check the status by using the IICAS0 and
IICAF0 registers each time interrupt INTIICA0 has occurred, and determine the processing to be
performed next.