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Table 2.2 Library specifications (2) 
 Item 
 Specifications 
 Remarks 
 Secure buffer 
 Work buffer: Work structure (approx. 530 bytes) 
 Ring buffer: Sector size * 10 bytes ~ 
 PCM buffer: 4096 * 2 ~ 4096 * 4sample / 1ch 
 Pause processing work: 4096sample ~ PCM buffer size 
 Fixed size 
 5 ) 
 6) 
 Only 
 is required when performing a pause 
 CPU load 
 | After playback starts | 
 | Task function | 
 | CPU occupancy 7) | 
 PCM uncompressed 44kHz stereo 16bit: 10% 
 PCM uncompressed 44kHz monaural 16bit: 6% 
 ADPCM compressed 44kHz stereo 16bit: 33% 
 ADPCM compressed 37.8kHz stereo 16bit: 29% 
 ADPCM compression 22kHz stereo 16bit: 17% 
 ADPCM compression 11kHz stereo 16bit: 8% 
 ADPCM compression 11kHz monaural 16bit: 4% 
 CD → Work 
 Memory → Sound 
 Memory transfer 
, etc. For ADPCM 
, all processing including decompression processing 
 
 Measured time 
 is. 
 PCM_Task (task 
 function) specifications 
-Frequency of V blank interrupt (1 time / 16ms) and 
 Call with equal or higher frequency. 
-Maximum processing time for one task function 
 PCM uncompressed stereo 16 bit: 15 ms 
 PCM uncompressed monaural 16 bit: 8 ms 
 ADPCM compressed stereo 16 bit: 34 ms 
 ADPCM compressed monaural 16 bit: 15ms 
 If 
 calls are made at an appropriate frequency 
, it takes 1 
 times between 
 during long processing. Degree 

 
     1) Designated ADPCM format is output by CRC Research Institute's Audio Starck tool (AIFF → ADPCM conversion tool)
It corresponds to the data. 
    
2) CD-ROM XA Audio has 16bit PCM data ADPCM compressed to 4bit and has the following format.
Refer to the CD-ROM XA standard for details.
B mode (37.8kHz) stereo / monaural
C mode (18.9kHz) stereo / monaural
∙ Only the stream playback mode can be used when playing CD-ROM XA Audio. 
    
3) There are two ways to use the memory playback mode.

       
    •  Plays a small file with the entire file already prepared in memory.

    •  Data read from the CD by the user is played while being sequentially supplied to the ring buffer. 
    
4) Some functions are not linked.
 ADPCM decompression library is not linked unless ADPCM use declaration PCM_DeclareUseAdpcm.
∙ File system and stream system are not linked in memory playback mode.
∙ Stream system is not linked in file playback mode.
In stream playback mode, both the file system and stream system are linked.

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