VIPER
Detailed hardware description
Audio
A National Semiconductor LM4548A AC’97 audio CODEC is used to support the audio
features of the VIPER. Audio inputs supported by the LM4548A are stereo line in and a
mono microphone input.
The LM4548A provides a stereo line out that can also be amplified by a National
Semiconductor LM4880 250mW per channel power amplifier, suitable for driving an 8
Ω
load. The LM4548A AC’97 codec may be turned off if it is not required. See the section
, for details.
Connection to the VIPER Audio features is via header PL6. See the table below for pin
assignments and the section
, for connector and mating
connector details.
Function Pin
Signal
Signal levels (max)
10 MIC
Microphone
7
Audio ground reference.
1Vrms input
1
Line input left
5
Line input right
Line in
3
Audio ground reference
1Vrms input
2
Line output left
6
Line output right
Line out
4
Audio ground reference
1Vrms output
8 Amp
output
left
11 Amp
output
right
Amp out
12
Audio ground reference
1.79Vpeak output,
1.26Vrms output (8
Ω
load)
223mW
© 2004 Arcom Issue H
38
