RX610 Group
22. I
2
C Bus Interface (RIIC)
R01UH0032EJ0120 Rev.1.20
Page 760 of 1006
Feb 20, 2013
The RIIC detects arbitration lost during transmission of NACK when the following condition is met with the NALE bit in
ICFER set to 1 (arbitration lost detection during NACK transmission enabled).
[Condition for arbitration lost during NACK transmission]
•
When the internal SDA output level does not match the SDAn line (ACK is received) during transmission of NACK
(ACKBT bit = 1 in ICMR3)
22.9.3
Slave Arbitration Lost Detection (SALE Bit)
The RIIC has a function to cause arbitration to be lost if the data for transmission (i.e. the internal SDA output level) and
the level on the SDAn line do not match (the high output as the internal SDA output; i.e. the SDAn pin is in the
high-impedance state) and the low level is detected on the SDA line in slave transmitter mode. This arbitration lost
detection function is mainly used when transmitting a UDID (Unique Device Identifier) over an SMBus.
When it loses slave arbitration, the RIIC is immediately released from the slave-matched state and enters slave receiver
mode. This function can detect conflicts of data during transmission of UDIDs over an SMBus and eliminates subsequent
redundant processing (processing for the transmission of FFh).
The RIIC detects slave arbitration lost when the following condition is met with the SALE bit in ICFER set to 1 (slave
arbitration lost detection enabled).
[Condition for slave arbitration lost]
•
When transmit data excluding acknowledge (internal SDA output level) does not match the SDAn line in slave
transmit mode (MST and TRS bits = 01b in ICCR2)
8
2
3
4
5
6
7
Data
8
2
3
4
5
6
7
Data
9
9
1
Transmit data mismatch
(Arbitration lost)
Release SCLn/SDA
2
3
4
2
3
4
5
0
6
7
8
9
5
1
1
1
1
2
3
4
5
6
Data
3
4
5
6
[Conflict during data transmission]
ACK
ACK
ACK
Write data to ICDRT
Clear AL to 0
TRS
AL
MST
BBSY
TDRE
SCLn
SDAn
SCLn
SDAn
Figure 22.35 Example of Slave Arbitration Lost Detection (SALE = 1)
Summary of Contents for RX600 Series
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