MAX 10 NEEK
60
www.terasic.com
February 4, 2016
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There is a high-sensitive microphone on the NEEK 10 board to receive the surrounding sound. After
the sound is collected and amplified approximately 392 times, as shown in
Figure 5-10
. It is feed
into the ADC of MAX 10 device. The digitized waveform will be displayed on the LCD.
Meanwhile the signal will be sent to the Line-out via audio codec and DAC SMA OUT connector.
Both of which can be connected to an external speaker. The data will also be processed based on the
volume to be displayed on the 10 LEDs onboard.
Figure 5-10 Onboard microphone amplifier with Gain (R24/R25) = 392
Function Block Diagram
Figure 5-11
is the function block diagram of this demonstration. The built-in MIC is amplified
approximately 392 times via two operational amplifiers. The signal is then feed into the ADC of
MAX 10 device for conversion. This demonstration uses the timing from the audio codec
((TLV320AIC3254) via I2S protocol to sync the entire system. The module SPI_CTL sets the
registers for the audio codec. The module SOUND_SUM syncs the digitized signal coming out of
the ADC of the MAX 10 device with the system and converts the data format i.e. adjust unsign
12-bit to sign 16-bit etc. The module SOUND2LCD converts the digitized sound signal into the
format of LCD timing to the LCD panel to be displayed in graphical sound wave. The module
DAC16 converts the digitized signal in parallel to 16-bit serial format for the DAC chip (DAC8551)
to the Line-out via audio codec (TLV320AIC3254). The module LED_METER displays the volume
of the sound on the 10 LEDs onboard.