HD6432138SW datasheet(542/1061 Pages) RENESAS

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Section 16 I

2C Bus Interface [H8S/2138 Group Option]

Rev. 4.00 Jun 06, 2006 page 488 of 1004

REJ09B0301-0400

Writing to ICDR and clearing of the IRIC flag must be executed continuously, so that no

interrupt is inserted.

If a period of time that is equal to transfer one byte has elapsed by the time the IRlC flag is

cleared, the end of transfer cannot be identified.

The master device sequentially sends the transmit clock and the data written to ICDR with the

timing shown in figure 16.7. The selected slave device (i.e. , the slave device with the

matching slave address) drives SDA low at the 9th transmit clock pulse and returns an

acknowledge signal.

[7] When one frame of data has been transimitted, the IRIC flag is set to 1 at the rise of the 9th

transmit clock pulse. After one frame has been transmitted, SCL is automatically fixed low in

synchronization with the internal clock until the next transmit data is written.

[8] Read the ACKB bit to confirm that ACKB is 0. When the slave device has not returned an

acknowledge signal and ACKB remains 1, execute the transmit end processing described in

step [12] and perfrom transmit operation again.

[9] Write the next data to be transmitted in ICDR. To indicate the end of data transfer, clear the

IRIC flag to 0.

As described in step [6] above, writing to ICDR and clearing of the IRIC flag must be

executed continuously so that no interrupt is inserted.

The next frame is transmitted in synchronization with the internal clock.

[10] When one frame of data has been transmitted, the IRIC flag is set to 1 at the rise of the 9th

transmit clock pulse. After one frame has been transmitted, SCL is automatically fixed low in

synchronization with the internal clock until the next transmit data is written.

[11] Read the ACKB bit of ICSR. Confirm that the slave device has returned an acknowledge

signal and ACKB is 0. When more data is to be transmitted, return to step [9] to execute next

transmit operation. If the slave device has not returned an acknowledge signal and ACKB is 1,

execute the transmit end processing described in step [12].

[12] Clear the IRIC flag to 0. Write BBSY and SCP of ICCR to 0. By doing so, SDA is changed

from low to high while SCL is high and the transmit stop condition is generated.

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