HD6432633 Datasheet, PDF (911/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

• Notes on ICDR Reads in Transmit Mode and ICDR Writes in Receive Mode
When attempting to read ICDR in the transmit mode (TRS = 1) or write to ICDR in the receive
mode (TRS = 0) under certain conditions, the SCL pin may not be held low after the
completion of the transmit or receive operation and a clock may not be output to the SCL bus
line before the ICDR register access operation can take place properly.
When accessing ICDR, always change the setting to the transmit mode before performing a
read operation, and always change the setting to the receive mode before performing a write
operation.
• Notes on ACKE Bit and TRS Bit in Slave Mode
When using the I²C bus interface, if an address is received in the slave mode immediately after
1 is received as an acknowledge bit (ACKB = 1) in the transmit mode (TRS = 1), an interrupt
may be generated at the rising edge of the 9th clock cycle if the address does not match.
When performing slave mode operations using the IIC bus interface module, make sure to do
the following.
(1) When a 1 is received as an acknowledge bit for the final transmit data after completing a
series of transmit operations, clear the ACKE bit in the ICCR register to 0 to initialize the
ACKB bit to 0.
(2) In the slave mode, change the setting to the receive mode (TRS = 0) before the start
condition is input. To ensure that the switch from the slave transmit mode to the slave
receive mode is accomplished properly, end the transmission as described in figure 18-19,
Flowchart for Slave Transmit Mode (Example), in section 18.3.10, Sample Flowcharts.
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