Renesas RX Series User Manual

R01UH0823EJ0100 Rev.1.00 Page 1178 of 1823
Jul 31, 2019
RX23W Group 35. I
2
C-bus Interface (RIICa)
35.10 Start Condition/Restart Condition/Stop Condition Issuing Function
35.10.1 Issuing a Start Condition
The RIIC issues a start condition when the ICCR2.ST bit is set to 1.
When the ST bit is set to 1, a start condition issuance request is made and the RIIC issues a start condition when the
ICCR2.BBSY flag is 0 (bus free state). When a start condition is issued normally, the RIIC automatically shifts to the
master transmit mode.
A start condition is issued in the following sequence.
Start condition issuance
(1) Drive the SDA0 line low (high level to low level).
(2) Ensure the time set in the ICBRH register and the start condition hold time.
(3) Drive the SCL0 line low (high level to low level).
(4) Detect low level of the SCL0 line and ensure the low-level period of SCL0 line set in the ICBRL register.
35.10.2 Issuing a Restart Condition
The RIIC issues a restart condition when the ICCR2.RS bit is set to 1.
When the RS bit is set to 1, a restart condition issuance request is made and the RIIC issues a restart condition when the
ICCR2.BBSY flag is 1 (bus busy state) and the ICCR2.MST bit is 1 (master mode).
A restart condition is issued in the following sequence.
Restart condition issuance
(1) Release the SDA0 line.
(2) Ensure the low-level period of SCL0 line set in the ICBRL register.
(3) Release the SCL0 line (low level to high level).
(4) Detect a high level of the SCL0 line and ensure the time set in the ICBRL register and the restart condition setup
time.
(5) Drive the SDA0 line low (high level to low level).
(6) Ensure the time set in the ICBRH register and the restart condition hold time.
(7) Drive the SCL0 line low (high level to low level).
(8) Detect a low level of the SCL0 line and ensure the low-level period of SCL0 line set in the ICBRL register.
Figure 35.37 Start Condition/Restart Condition Issue Timing (ST and RS Bits)
[Start condition issuing operation]
[Restart condition issuing operation]
Write 1 to ST bit
ICBRH ICBRL
Write 1 to RS bit
ICBRH ICBRLICBRLICBRLICBRH
ACK/NACK
S8
Sr
Hold time Hold timeSetup time
Accept restart condition issuance
Accept start condition issuance
Issue start
condition
TRS
START
MST
BBSY
IIC

TDRE
ST
TRS
RS
MST
BBSY
IIC

TDRE
START
Issue restart
condition
SCL0
SDA0
SCL0
SDA0

Renesas RX Series Specifications

General

Brand	Renesas
Model	RX Series
Category	Microcontrollers
Language	English