User`s guide

MPLAB STARTER KIT FOR

dsPIC

DIGITAL SIGNAL CONTROLLERS

USER’S GUIDE

Chapter 2. Speech Record and Playback Demo

This chapter describes the Speech Record and Playback Demonstration application

that is preloaded on the dsPIC33F device. This application demonstrates how to use

the starter kit for speech capture, speech playback, speech encoding and decoding,

and using the serial Flash memory to store speech samples. Topics covered include:

• Running the Demo

• Understanding the Demo

• Examining Demo Software Flow

• Other Demo Code Examples

2.1 RUNNING THE DEMO

To run the demo, follow these basic steps:

1. Connect a microphone to socket J9. Connect a headphone to socket J8. Ensure

that potentiometer R56 is set to the factory setting, i.e., the arrow on the

potentiometer points to the arrow on the board.

2. Power up the starter kit by connecting the board to the USB port of a computer.

You should briefly see a pop-up balloon in the system tray (lower right of desktop)

that states (1) new hardware has been found, (2) drivers are being installed, and

(3) new hardware is ready for use. If you do not see these messages and then

the starter kit does not work, try reconnecting the USB. If this does not work, see

Section 3.8 “Troubleshooting”.

3. When powered up, the application will repeatedly play back an introductory

message.

To use the application, follow these steps:

1. To record speech, press switch S1 and wait till the Red LED turns off (the serial

Flash memory is being erased) and the Yellow LED turns on. The application will

now record the microphone audio signals and store them in the serial Flash

memory.

2. Press switch S2 to playback and listen to the stored speech samples. The Green

LED turns on during playback.

3. Pressing switch S1 again erases the serial Flash memory and prepares the

system for another recording.