HD64F2149YV datasheet(558/1075 Pages) RENESAS

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Section 16 I

2C Bus Interface

Rev. 3.00 Jan 18, 2006 page 530 of 1044

REJ09B0280-0300

16.3.4

Slave Receive Operation

In slave receive mode, the master device outputs the transmit clock and transmit data, and the

slave device returns an acknowledge signal. The reception procedure and operations in slave

receive mode are described below.

[1] Set the ICE bit in ICCR to 1. Set the MLS bit in ICMR and the MST and TRS bits in ICCR

according to the operating mode.

[2] When the start condition output by the master device is detected, the BBSY flag in ICCR is set

to 1.

[3] When the slave address matches in the first frame following the start condition, the device

operates as the slave device specified by the master device. If the 8th data bit (R/

W) is 0, the

TRS bit in ICCR remains cleared to 0, and slave receive operation is performed.

[4] At the 9th clock pulse of the receive frame, the slave device drives SDA low and returns an

acknowledge signal. At the same time, the IRIC flag in ICCR is set to 1. If the IEIC bit in

ICCR has been set to 1, an interrupt request is sent to the CPU. If the RDRF internal flag has

been cleared to 0, it is set to 1, and the receive operation continues. If the RDRF internal flag

has been set to 1, the slave device drives SCL low from the fall of the receive clock until data

is read into ICDR.

[5] Read ICDR and clear the IRIC flag in ICCR to 0. The RDRF flag is cleared to 0.

Receive operations can be performed continuously by repeating steps [4] and [5]. When SDA is

changed from low to high when SCL is high, and the stop condition is detected, the BBSY flag in

ICCR is cleared to 0.

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