AN706-00040-2v0-E
71
No
Yes
music1.aac
music2.aac
music3.aac
music4.aac
music5.aac
Media files
USB-MSC device connection/
disconnection judgement
Was media disconnected?
Stop AAC play
Swith press detection
Switch
state
Yes
No
Close AAC file
End file system
Change to initialization state
Switch detection module
Play/Stop
switch
Selection
previous
switch
Selection
next switch
Switch chattering
processing
Timer interrupt(ch.2)(1ms)
Are there enough empty
area in the input buffer?
Read AAC data from media
and copy in the input buffer
One frame of the data in the
input buffer is decoded, then
store it to the RAW buffer
Was one frame
decoded successful?
Up-sample the RAW buffer data
and copy it to the output buffer
Sampling data
output module
PCM
data
PCM
data
I
2
S
output
No
No
Yes
Yes
Output
buffer
DMA interrupt(ch.2)
Was the Play/Stop
switch pressed?
Stop AAC play
Close MP3 file
Change to audio data
playback stop state
Figure 51 Application Operation Flow (Audio Playback Status, Case of AAC)
