Renesas RX Series User Manual

R01UH0823EJ0100 Rev.1.00 Page 1177 of 1823
Jul 31, 2019
RX23W Group 35. I
2
C-bus Interface (RIICa)
Condition for arbitration-lost during NACK transmission
 When the internal SDA output level does not match the SDA0 line (ACK is received) during transmission of NACK
(ICMR3.ACKBT bit = 1)
35.9.3 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 SDA0 line do not match (the high output as the internal SDA output; i.e. the SDA0 pin is in the high-
impedance state and the low level is detected on the SDA0 line in slave transmit 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 receive
mode. This function can detect conflicts of data during transmission of UDIDs over an SMBus and eliminate subsequent
redundant processing (processing for the transmission of FFh).
The RIIC detects slave arbitration-lost when the following condition is met with the ICFER.SALE bit 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 SDA0 line in slave
transmit mode (bits MST and TRS in the ICCR2 register are 01b)
Figure 35.36 Example of Slave Arbitration-Lost Detection (SALE = 1)
8234567
Data
8234567
Data
9
9
1
Transmit data mismatch
(Arbitration lost)
Release SCL/SDA
2 3 4
2 3 4 5
0
6 7 8 9
5
1
1
1
1 23456
Data
3456
[Conflict during data transmission]
ACK
ACK
ACK
Write data to ICDRT register
Clear AL flag to 0
TRS
AL
MST
BBSY
TDRE
SCL0
SDA0
SCL0
SDA0

Renesas RX Series Specifications

General

Brand	Renesas
Model	RX Series
Category	Microcontrollers
Language	English