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Chapter 3
Audio Interface (J9)
The audio solution on the LittleBoard 800 is provided by the Realtek ALC202A audio CODEC. The
chip is defined by AC97 and is revision 2.2 compliant. The audio interface signals are supplied to the
26-pin 2mm connector (J9). Refer to the following list for the Audio CODEC (ALC202A) features.
• Analog Mixer Dynamic Range 97dB (typ)
• D/A Dynamic Range 89dB (typ) and A/D Dynamic Range 90dB (typ)
• AC'97 Rev 2.1 compliant
• High quality Sample Rate Conversion (SRC) from 4kHz to 48kHz
• 3D Sound circuitry and PC-Beep passthrough to Line Out while reset is held active low
• True Line Level Output with volume control independent of Line Out
Table 3-22 describes the pin-outs and signals of the audio interface and it has 26 pins, 2 rows, odd/even,
(1, 2) with 2mm pin spacing.
Table 3-22. Audio Interface Pin/Signal Descriptions (J9)
Pin #
Signal
1
VIDEO_L
2
VIDEO_GND
3
VIDEO_R
4
CD_L
5
CD_GND
6
CD_R
7
LINE_IN_L
8
LINE_IN_GND
9
LINE_IN_R
10
MIC1
11
MIC_GND
12
MIC2
13
MIC_REF
14
NC/KEY
15
PHONE_IN
16
PHONE_GND
17
MONO_OUT
18
MONO_GND
19
+AOUT_L
20
-AOUT_L
21
+AOUT_R
22
-AOUT_R
23
GND
24
HP_L
25
HP_R
26
NC
Note: The shaded area denotes power or ground.
LittleBoard 800
Description
Video-Audio signal in left channel
Video Audio ground
Video-Audio signal in right channel
CD-ROM signal left channel
CD-ROM Audio ground
CD-ROM signal right channel
Line in signal left channel
Line in Audio ground
Line in signal right channel
Microphone in signal 1 or left channel
Microphone Audio ground
Microphone in signal 2 or right channel
Microphone reference signal
Not Connected - Key
Phone signal in
Phone Audio ground
Monaural signal out
Monaural Audio ground
- Audio out signal left channel
+ Audio out Audio ground
- Audio out signal right channel
+ Audio out Audio ground
Audio Ground (tied to all audio grounds)
Headphone signal left channel
Headphone signal right channel
Not Connected
Reference Manual
Hardware
53
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