M10 Hardware Design
capacitor is recommended ) which usually for block the DC voltage in the single-end mode.
The module analogy output configuration is determined by control register settings and
established using analogy multiplexes.
These two analogy channels can be easily swapped by "AT+QAUDCH" command. For more
details, please refer to document [1].
For each channels, you can use AT+QMIC to adjust the input gain level of microphone, you
can also use "AT+CLVL" to adjust the output gain level of receiver and speaker.
"AT+QECHO" is to set the parameters for echo cancellation control. Also "AT+QSIDET" is
to set the side-tone gain level, use "AT+QAUDCH" to activate one of the two audio channels
and deactivate the other one. For details, please refer to document [1].
Note:
Use AT command "AT+QAUDCH" to select audio channel:
0--AIN1/AOUT1 (normal audio channel), the default value is 0.
1--AIN2/AOUT2 (aux_audio channel) .
Table 11: Pin definition of Audio interface
Interface
Name
MIC1P
MIC1N
(AIN1/AOUT1)
SPK1P
SPK1N
MIC2P
(AIN2/AOUT2)
MIC2N
SPK2P
AGND
One of the following matching circuits can be chosen in order to improve audio performance. The
difference audio signals have to be layout according to differential signal layout rules. As show in
following figures (Note: all components package are 0603.) If you want to adopt an amplifier
circuit for audio, Texas Instruments's TPA6205A1 which is a fully differential amplifier is
recommended. You can also select it according to your requirement.
M10_HD_V1.00
Pin
Function
23
Microphone1 input +
24
Microphone1 input -
22
Audio1 output+
21
Audio1 output-
25
Microphone2 input +
26
Microphone2 input -
20
Audio2 output+
19
Suggest to be used in audio circuit. Don't
connect to digital GND.
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