Application overview

AN3997

4/15

Doc ID 022390 Rev 1

2

Application overview

2.1

Application description

The audio playback and record applications support two types of mass storage media. They

can play audio data in the internal Flash of the microcontroller or on an external USB key,

and record data only to an external USB key. This is selected by defines in the main.h file. In

the workspace toolbar, select the project configuration:

●

MEDIA_IntFLASH

●

MEDIA_USB_KEY

The firmware driver can:

●

Play a stored wave from an external USB key or internal Flash

●

Record a wave in an external USB key

●

Switch from play to record

Figure 1.

Audio playback and record architecture

This application is based on a STM32F4xx device and an STM32F4-DISCOVERY board.

The main features of the application are:

●

MEMS microphone

●

Audio Codec DAC

●

Headphone

●

USB key (if this the storage media used)

●

MEMS accelerometer

MS19886V1

Codec

(DAC)

I2S

Button

USB

host