VS1053B Datasheet, PDF(52/79 Page) List of Unclassifed Manufacturers

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VS1053B Datasheet, PDF (52/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC

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VLSI

Solution y

VS1053b preliminary

VS1053B

9. OPERATION

9.6 Feeding PCM data

VS1053b can be used as a PCM decoder by sending a WAV ï¬le header. If the length sent in the WAV

header is 0 or 0xFFFFFFFF, VS1053b will stay in PCM mode indeï¬nitely (or until SM CANCEL has

been set). 8-bit linear and 16-bit linear audio is supported in mono or stereo. A WAV header looks like

this:

File Offset Field Name

Size Bytes

Description

0 ChunkID

4 "RIFF"

4 ChunkSize

4 0xff 0xff 0xff 0xff

8 Format

4 "WAVE"

12 SubChunk1ID

4 "fmt "

16 SubChunk1Size

4 0x10 0x0 0x0 0x0 16

20 AudioFormat

2 0x1 0x0

Linear PCM

22 NumOfChannels 2 C0 C1

1 for mono, 2 for stereo

24 SampleRate

4 S0 S1 S2 S3

0x1f40 for 8 kHz

28 ByteRate

4 R0 R1 R2 R3

0x3e80 for 8 kHz 16-bit mono

32 BlockAlign

2 A0 A1

2 for mono, 4 for stereo 16-bit

34 BitsPerSample

2 B0 0xB1

16 for 16-bit data

52 SubChunk2ID

4 "data"

56 SubChunk2Size

4 0xff 0xff 0xff 0xff Data size

The rules to calculate the four variables are as follows:

â¢ S = sample rate in Hz, e.g. 44100 for 44.1 kHz.

â¢ For 8-bit data B = 8, and for 16-bit data B = 16.

â¢ For mono data C = 1, for stereo data C = 2.

â¢

C ÃB

â¢ R = S Ã A.

Example: A 44100 Hz 16-bit stereo PCM header would read as follows:

0000 52 49 46 46 ff ff ff ff 57 41 56 45 66 6d 74 20

0100 10 00 00 00 01 00 02 00 44 ac 00 00 10 b1 02 00

0200 04 00 10 00 64 61 74 61 ff ff ff ff

|RIFF....WAVEfmt |

|........D.......|

|....data....|

9.7 Ogg Vorbis Recording

Ogg Vorbis is an open ï¬le format that allows for very high sound quality with low to medium bitrates.

Ogg Vorbis recording is activated by loading the Ogg Vorbis Encoder Application to the 16 KiB program

RAM memory of the VS1053b. After activation, encoder results can be read from registers SCI HDAT0

and SCI HDAT1, much like when using ADPCM recording (Chapter 9.8).

Three proï¬les are provided: one for high-quality stereo recording at a bitrate of approx. 140 kbit/s, and

two for speech-quality mono recording at a bitrates between 15 and 30 kbit/s.

To use the Ogg Vorbis Encoder application, please load the application from VLSI Solutionâs Web page

http://www.vlsi.ï¬/software/plugins/plugins.shtml and read the accompanying documentation.

Version 0.5, 2007-12-03

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