User's Manual

MC55/56 Hardware Interface Description
Confidential / Preliminary
s
MC55/56_hd_v03.00 Page 86 of 104 16.08.2005
5.5.2 Audio programming model
The audio programming model shows how the signal path can be influenced by varying the
AT command parameters. The model is the same for all three interfaces, except for the
parameters <outBbcGain> and <inBbcGain> which cannot be modified if the digital audio
interface is being used, since in this case the DAC is switched off.
The parameters inBbcGain and inCalibrate can be set with AT^SNFI. All the other
parameters are adjusted with AT^SNFO.
A
D
A
D
-
∞
...0dB
Speech coder
neg. gain (attenuation)
0dB; -6db, -12dB; -18dB
+0...42dB in 6dB steps
1k
1k
1k
1k
2.65V
10uF
+
<sideTone>
A
T parameters are given in brackets <…>
and marked red and italic.
<outCalibrate[n]>
n = 0...4
<inCalibrate>
<inBbcGain>
<outBbcGain>
Speech decoder
MIC2
TFSDAI, TXDDAI
RFSDAI, RXDDAI
MIC1
<io>
<ep>
<mic>
Figure 37: Audio programming model