AK4145 Datasheet, PDF (17/27 Pages) Asahi Kasei Microsystems – Digital BTSC Stereo Encoder

[AK4145]
1-3. ACKNOWLEDGE
ACKNOWLEDGE is a software convention used to indicate successful data transfers. The device will release the SDA
line (HIGH) after transmitting the eight bits. The receiver must pull down the SDA line during the acknowledge clock
pulse so that that it remains stable “L” during “H” period of this clock pulse. The AK4145 will generate an acknowledge
after each byte is received.
In read mode, the slave device, the AK4145 will transmit the eight bits of data, release the SDA line and monitor the line
for an acknowledge. If an acknowledge is detected, the slave device will continue transmitting the data. If an
acknowledge is not detected, the slave device will terminate further data transmissions and await STOP condition.
Clock pulse
for acknowledge
SCL FROM
MASTER
1
8
9
DATA
OUTPUT BY
TRANSMITTER
DATA
OUTPUT BY
RECEIVER
START
CONDITION
Figure 9. Acknowledge on the I²C-bus
not acknowledge
acknowledge
1-4. FIRST BYTE
The first byte, which includes seven bits of slave address and one bit of R/W bit, is sent after the START condition. If the
transmitted slave address matches an address for one of the device, the receiver which is addressed pulls down the SDA
line.
The most significant seven bits of the slave address are fixed as “0010011”. The eighth bit (LSB) of the first byte (R/W
bit) defines whether the master requested a write or read condition. A “1” indicates that the read operation is to be
executed. A “0” indicates that the write operation is to be executed.
0
0
1
0
0
1
1
R/W
Figure 10. The First Byte
MS0982-E-01
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2010/09