This document outlines the process of playing music on a device. It involves: 1. The user pressing a button on the device which is distinguished by the CPU and a command signal is sent. 2. The command signal is received and the appropriate sound data is retrieved from memory and sent to the speaker or the display is changed. 3. For the music play command, the music file information is retrieved from memory and sent to the music player which plays the music and allows the user to control the volume.

7. Command
(for Button)
1.0
User
Input
Sound
Command
Signal
Display
2.0
SoundData
Output
3.0
Music
Play
Information
of Musicfile
MusicFile
D
Memory

8. 1.2
User
Information of
Pressed Button
Command
(for Button)
1.1
Distinguish
Pressed
Button
Decide
Command
Command
Signal
3.0
Music
Play

9. User
2.1
Sound
Send
Speaker
to Sound
SoundData
Display
2.2
Change
Display
3.0
Information
of Musicfile
and State
Music
Play

10. 3.2
Volume
Up/Down
Volume
Command
1.0
3.1
Distinguish
Command Command
Signal
Volume
Value
Input
Musicplay
Command
SoundData
2.0
3.3
Output
Player
Information
of Musicfile
D
MusicFile
Memory

11. (1092014 학우 PPT 참고해서 제작.)
User
OS
Play
Music
I/O interface
Input
Button
Record
Sound
메모리
Display
I/O
CPU
Hard Ware