TDA7300 Datasheet, PDF (11/16 Pages) STMicroelectronics – DIGITAL CONTROLLED STEREO AUDIO PROCESSOR

APPLICATION INFORMATION (continued)
Figure 23: Acknowledge on the I²CBUS
TDA7300
Transmission without Acknowledge
Avoiding to detect the acknowledge of the audio-
processor, the µP can use a simplier 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 and decreases the noise immunity.
Interface Protocol
The interface protocol comprises:
A start condition (S)
A chip address byte, containing the TDA7300
address (the 8th bit of the byte must be 0). The
TDA7300 must always acknowledge at the end
of each transmitted byte.
A sequence of data (N-bytes + acknowledge)
A stop condition (P)
TDA7300 ADDRESS
MSB first byte
LSB MSB
S 1 0 0 0 1 0 0 0 ACK
DATA
LSB MSB
ACK
DATA
LSB
ACK P
ACK = Acknowledge
S = Start
P = Stop
MAX CLOCK SPEED 100kbits/s
Data Transferred (N-bytes + Acknowledge)
SOFTWARE SPECIFICATION
Chip address (TDA7300 address)
1
0
0
0
1
0
MSB
0
0
IIII I LSB
DATA BYTES
MSB
00
11
11
10
10
01
01
01
LSB
B2 B1 B0 A2 A1 A0
0 B1 B0 A2 A1 A0
1 B1 B0 A2 A1 A0
0 B1 B0 A2 A1 A0
1 B1 B0 A2 A1 A0
0 X X S2 S1 S0
1 0 C3 C2 C1 C0
1 1 C3 C2 C1 C0
Function
Volume Control
Speaker ATT LR
Speaker ATT RR
Speaker ATT LF
Speaker ATT RF
Audio switch
Bass control
Treble control
X = don’t care
Ax = 2dB steps
Bx = 10dB steps
Cx = 2.5dB steps
Status after power-on reset
Volume
Speaker
Audio Switch
Bass
Treble
–68dB
–38dB
Mono
+2.5dB
+2.5dB
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