2 quick questions

#1

Hi everyone,

I’m quite new here and I have 2 quick questions.

1. What does AIC stand for?
I saw this in source code:
AudioInputI2S_F32 i2s_in; //Digital audio from the Tympan AIC.
also I saw:
AudioInputI2S_F32 i2s_in(audio_settings); //Digital audio input from the ADC

I know what ADC is but don’t know AIC.

2. Does the 3.5mm Audio jack for external microphone of Tympan RevD receive 2-channel signals?
I connect the audio jack with Roland CS-10EM earphone which has binaural microphones but only left microphone works.

Roland CS-10EM website:

Thanks in advance for any replies.

Tony

#2

Hi tony9773,

  1. Great question! The AIC (Analog Interface Circuit) offloads the Tympan by providing input sampling (ADC), signal processing, and headphone or line level output (DAC). Here is a link to the chip we are using (TLV320AIC3206). If you dig into the datasheet, you’ll see the many features of this chip. It sends audio back and forth to the Teensy using the I2S audio protocol.

  2. Yes, the Tympan can accept a stereo microphone.
    Below is a reference to the schematic showing the TRS jack connected to IN3_L (Tip); IN3_R (Ring); and GND (Sleeve).

To use an external microphone with a bias voltage, select the proper input using the following code:
myTympan.inputSelect(TYMPAN_INPUT_JACK_AS_MIC); // use the microphone jack - defaults to mic bias 2.5V

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