HD64F2149YV datasheet(546/1075 Pages) RENESAS

546 / 1075 page

Section 16 I

2C Bus Interface

Rev. 3.00 Jan 18, 2006 page 518 of 1044

REJ09B0280-0300

Bit 0—Acknowledge Bit (ACKB): Stores acknowledge data. In transmit mode, after the

receiving device receives data, it returns acknowledge data, and this data is loaded into ACKB. In

receive mode, after data has been received, the acknowledge data set in this bit is sent to the

transmitting device.

When this bit is read, in transmission (when TRS = 1), the value loaded from the bus line

(returned by the receiving device) is read. In reception (when TRS = 0), the value set by internal

software is read.

When writing to this bit, acknowledge data that is returned after receiving is rewritten regardless

of the TRS value. The data loaded from receiving device is retained, therefore pay attention when

using bit-manipulation instructions.

Bit 0

ACKB

Description

Receive mode: 0 is output at acknowledge output timing

(Initial value)

Transmit mode: Indicates that the receiving device has acknowledged the data (signal

is 0)

Receive mode: 1 is output at acknowledge output timing

Transmit mode: Indicates that the receiving device has not acknowledged the data

(signal is 1)

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