LC89091JA Datasheet, PDF (19/30 Pages) ON Semiconductor – Digital Audio Interface Receiver

LC89091JA
9. Microcontroller Interface
 The LC89091JA is controlled via I²C (Fast-mode, 400kHz).
9.1 Terminal Setup (SCL, SDA)
 The pull-up resistor is connected to SCL and SDA pins.
The resistor should take current and timing into consideration enough.
 If the clock line will not be Hi-Z state, the pull-up resistor of SCL may delete.
 When not using microcontroller, SCL and SDA make GND connection. In this case, initial value of register is set up.
9.2 Data Transfer
 I²C slave transceiver interface is based on ver2.1 (HS mode un-corresponding).
 At first, input Start condition and Slave-address, an acknowledge generates, WRITE operation and READ operation
(input Register-address and Control-data) is executed. After the command execution, input Stop condition.
 SDA line state must be constant while SCL is "H". State change on SDA line is restricted while SCL line is "L". If
SDA data changes while SCL line is "H", it will be recognized as Start condition or Stop condition.
SDA
SCL
data line
stable:
data valid
change
of data
allowed
Figure 9.1: Data transfer on I²C bus
9.3 Start and Stop Condition
 The Start condition is generated by the transition of "H" to "L" on SDA line while SCL line is "H".
 The Stop condition is generated by the transition of "L" to "H" on SDA line while SCL line is "H".
SDA
SCL
S
Start condition
Figure 9.2: Start and Stop Condition
P
Stop condition
9.4 Acknowledge
 After receiving bits (1 byte) of data, SDA line is released, LC89091JA will stabilize SDA line in "L" state.
This operation is called "acknowledgement".
 The LC89091JA generates an acknowledgement upon receipt of Start condition and Slave-address.
Furthermore, for a WRITE instruction, an acknowledgement is generated whenever receipt of each byte is completed.
For a READ instruction, succeeded by generation of an acknowledgement, the LC89091JA releases the SDA line
after outputting data at the designated address, and it monitors the SDA line condition.
When the microcontroller generates an acknowledgement without sending Stop condition, the LC89091JA outputs
data at the next address location. When no acknowledgement is generated, the LC89091JA ends data output (not
acknowledged).
No.A2172-19/30