VS1103B datasheet(40/61 Pages) ETC2

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VS1103b

VS1103B

7. OPERATION

7.4.4 Playing ADPCM Data

In order to play back your IMA ADPCM recordings, you have to have a ﬁle with a header as described

in Chapter 7.4.3. If this is the case, all you need to do is to provide the ADPCM ﬁle to VS1103 as an

ADPCM stream.

7.4.5 Sample Rate Considerations

VS10xx chips that support IMA ADPCM playback are capable of playing back ADPCM ﬁles with

any sample rate. However, some other programs may expect IMA ADPCM ﬁles to have some exact

sample rates, like 8000 or 11025 Hz. Also, some programs or systems do not support sample rates below

8000 Hz.

If SM RECORD PATH is set, recording is performed from the mixer output at exactly 44.1 kHz from

the mixer output. If SM RECORD PATH is not set, recording is performed at 8kHz × XT ALI

12.288M Hz from

the microphone or line input. From the formula it can be seen that the nominal 8 kHz sample rate can

only be obtained if XTALI = 12.288 MHz. Example: If you have a 12 MHz clock, you will get a sample

rate of 7812.5 Hz, which should be recorded to the ﬁle.

7.4.6 Example Code

The following code initializes IMA ADPCM encoding on VS1103 and shows how to read the data.

const unsigned char header[] = {

0x52, 0x49, 0x46, 0x46, 0x1c, 0x10, 0x00, 0x00,

0x57, 0x41, 0x56, 0x45, 0x66, 0x6d, 0x74, 0x20, /*|RIFF....WAVEfmt |*/

0x14, 0x00, 0x00, 0x00, 0x11, 0x00, 0x01, 0x00,

0x40, 0x1f, 0x00, 0x00, 0x75, 0x12, 0x00, 0x00, /*|........@......|*/

0x00, 0x01, 0x04, 0x00, 0x02, 0x00, 0xf9, 0x01,

0x66, 0x61, 0x63, 0x74, 0x04, 0x00, 0x00, 0x00, /*|.......fact....|*/

0x5c, 0x1f, 0x00, 0x00, 0x64, 0x61, 0x74, 0x61,

0xe8, 0x0f, 0x00, 0x00

};

unsigned char db[512]; /* data buffer for saving to disk */

Version 1.01, 2007-09-03

VS1103B 数据表(PDF) 40 Page - List of Unclassifed Manufacturers