Specifications

Chapter 3 Hardware
LittleBoard 735 Reference Manual 31
Audio Interface
The audio solution on the LittleBoard 735 is provided by the Realtek ALC203-LF 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 (ALC203-LF) 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 3-13 describes the pin signals of the audio interface which uses 26 pins, 2 rows, odd/even sequence (1,
2) with 0.079" (2mm) pitch.
Note: The shaded areas denote power or ground.
Table 3-13. Audio Interface Pin Signals (J9)
Pin # Signal Description
1 NC Not connected (Video Audio In signal left channel)
2
VIDEO_GND Video Audio ground
3 NC Not connected (Video Audio In signal right channel)
4 CD_L CD-ROM signal left channel
5
CD_GND CD-ROM Audio ground
6 CD_R CD-ROM signal right channel
7 LINE_IN_L Line In signal left channel
8
LINE_IN_GND Line In Audio ground
9 LINE_IN_R Line In signal right channel
10 MIC1 Microphone In signal 1 or left channel
11
MIC_GND Microphone Audio ground
12 MIC2 Microphone In signal 2 or right channel
13 MIC_REF Microphone reference signal
14 NC/KEY Not Connected - Key
15 PHONE_IN Phone signal In
16
PHONE_GND Phone Audio ground
17 MONO_OUT Monaural signal Out
18
MONO_GND Monaural Audio ground
19 +AOUT_L + Audio Out signal Left channel
20
-AOUT_L - Audio Out Left ground
21 +AOUT_R + Audio Out signal Right channel
22
-AOUT_R - Audio Out Right ground
23
GND Audio Ground (tied to all audio grounds)
24 HP_L Headphone signal Left channel
25 HP_R Headphone signal Right channel
26 NC Not Connected (Headphone In)