Slave Arbitration-Lost Detection (Sale Bit) - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
transmission processing) necessary if the UDID (Unique Device Identifier) of assign address does not
match in the Get UDID (general) processing after the Assign address command.
The RIIC detects arbitration-lost during transmission of NACK when the following condition is met
with the RIICnFER.NALE bit 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 SDA line (ACK is received) during
transmission of NACK (RIICnMR3.ACKBT bit = 1)
18.11.3

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 SDA line do not match (the high output as the internal SDA output;
i.e. the SDA pin is in the highimpedance state) and the low level is detected on the SDA 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 enters slave receive 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 FF
The RIIC detects slave arbitration-lost when the following condition is met with the RIICnFER.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 SDA line
in slave transmit mode (RIICnCR2.MST and TRS bits = 01
[Conflict during data transmission]
SCLn
SDAn
SCLn
SDAn
BBSY
MST
TRS
AL
TDRE
Figure 18.36
R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
2 3 4 5 6 7 8
ACK
Data
2 3 4 5 6 7 8
ACK
Data
Example of Slave Arbitration-Lost Detection (SALE = 1)
)
B
9 1 2 3 4 5
1 1
9 1 2 3 4 5
0
Write data to RIICnDRT
18. I²C Bus Interface
).
H
Transmit data mismatch
(Arbitration-lost)
6 7 8 9 1 2 3 3
ACK
Data
Clear AL to 0
Release SCLn/SDA
4 4 5 5 6 6
18-80