FUJITSU FMB AN706 User Manual
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AN706-00040-2v0-E
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(2) The application operation flow with audio data playback in progress is as follows.
① USB MSC device connection/disconnection judgment is executed in the main
loop.
② If the USB memory has been removed, stop playback, close the opened AAC file,
quit the file system and operation shifts to initialization status.
③ If the USB memory is connected, play/stop button press-down detection is
executed.
④ If the play/stop button is detected to have been pressed down, playback stops,
the AAC file is closed, and operation shifts to audio data playback stop status.
⑤ Verify vacancy of input buffer.
⑥ If there is sufficient vacancy, the AAC file is read from the USB memory and
copied in the input buffer.
⑦ One elementary stream of the input buffer is decoded and stored in the RAW
buffer.
⑧ When 1 elementary stream had been decoded, the RAW buffer is up-sampled
and buried in the output buffer.
⑨ With DMA ch2 interrupt, data is sent from the output buffer to I
2
S in sequence.
This operation is shown in Figure 51.