Microphone Interface

For the microphone interface we are using an electret microphone breakout board. This board includes a microphone amplifier the MAX4466 with an adjustable gain. For this assignment we want to read the microphone’s analog output and display it on the LED’s located on your development board. In order to complete this assignment remember the following:

1. You must sample the microphone signal at the highest rate the ADC chip / core will allow.
2. The microphone delay design must update the LED’s at a rate of at least 40kHz so that all sound human ears can hear will be displayed on the LEDs.

Setup

Your FPGA development board will be required to have the capability to perform Analog to Digital conversions. If you’re using a Xilinx part that has XADC capability we will use that to perform the ADC operations. Otherwise the development board will need to interface with an external ADC chip. See the microphone breakout board below:

The microphone can be purchased at Adafruits online retail store:

https://www.adafruit.com/product/1063

Verification

To verify that your design is working properly take the microphone out wire and connect it to Vcc (3.3V or 5.0V) and see that all the LED’s on the development board should light up. Then connect the output wire to ground and all the LED’s should turn off.