TDA7430_04 Datasheet, PDF (9/23 Pages) STMicroelectronics – DIGITALLY CONTROLLED AUDIO PROCESSOR WITH SURROUND SOUND MATRIX AND VOICE CANCELLER

TDA7430 - TDA7431
Table 5. Electrical Characteristcs (continued)
Symbol
Parameter
d
Distorsion
S_C Channel Separation
V_OCL Clipping Level
R_OUT Output Resistance
V_OUT DC Voltage Level
BUS INPUTS
V_IL Input Low Voltage
V_IH Input High Voltage
I_IN Input Current
V_O Output Voltage SDA
Acknowledge
Test Condition
A_v = 0 ; V_in = 1V_rms
d = 0.3%
I_O = 1.6mA
Min.
70
2
10
Typ.
0.01
90
2.5
40
3.8
Max.
0.1
70
Unit
%
dB
Vrms
Ω
V
1
V
3
V
-5
+5
mA
0.4
V
3 I²C BUS INTERFACE
Data transmission from microprocessor to the TDA7430/TDA7431 and viceversa takes place through the 2
wires I²C BUS interface, consisting of the two lines SDA and SCL (pull-up resistors to positive supply voltage
must be connected).
3.1 Data Validity
As shown in fig. 8, the data on the SDA line must be stable during the high period of the clock. The HIGH and
LOW state of the data line can only change when the clock signal on the SCL line is LOW.
3.2 Start and Stop Conditions
As shown in fig.9 a start condition is a HIGH to LOW transition of the SDA line while SCL is HIGH. The stop
condition is a LOW to HIGH transition of the SDA line while SCL is HIGH.
3.3 Byte Format
Every byte transferred on the SDA line must contain 8 bits. Each byte must be followed by an acknowledge bit.
The MSB is transferred first.
3.4 Acknowledge
The master (µP) puts a resistive HIGH level on the SDA line during the acknowledge clock pulse (see fig. 10).
The peripheral (audioprocessor) that acknowledges has to pull-down (LOW) the SDA line during this clock
pulse.
The audioprocessor which has been addressed has to generate an acknowledge after the reception of each
byte, otherwise the SDA line remains at the HIGH level during the ninth clock pulse time. In this case the master
transmitter can generate the STOP information in order to abort the transfer.
3.5 Transmission without Acknowledge
Avoiding to detect the acknowledge of the audioprocessor, the µP can use a simpler transmission: simply it
waits one clock without checking the slave acknowledging, and sends the new data.
This approach of course is less protected from misworking.
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