VS1003 datasheet(39/61 Pages) VLSI

39 / 61 page

VS1003

OPERATION

Note: if SCI_HDAT1 ≥ 896, it may be better to wait for the buffer to overﬂow and clear before

reading samples. That way you may avoid buffer aliasing.

Each IMA ADPCM block is 128 words, i.e. 256 bytes. If you wish to interrupt reading data

and possibly continue later, please stop at a 128-word boundary. This way whole blocks are

skipped and the encoded stream stays valid.

9.4.3

Adding a RIFF Header

To make your IMA ADPCM ﬁle a RIFF / WAV ﬁle, you have to add a header before the actual

data. Note that 2- and 4-byte values are little-endian (lowest byte ﬁrst) in this format:

File Offset

Field Name

Size

Bytes

Description

ChunkID

"RIFF"

ChunkSize

F0 F1 F2 F3

File size - 8

Format

"WAVE"

SubChunk1ID

"fmt "

SubChunk1Size

0x14 0x0 0x0 0x0

AudioFormat

0x11 0x0

0x11 for IMA ADPCM

NumOfChannels

0x1 0x0

Mono sound

SampleRate

R0 R1 R2 R3

0x1f40 for 8 kHz

ByteRate

B0 B1 B2 B3

0xfd7 for 8 kHz

BlockAlign

0x0 0x1

0x100

BitsPerSample

0x4 0x0

4-bit ADPCM

ByteExtraData

0x2 0x0

ExtraData

0xf9 0x1

Samples per block (505)

SubChunk2ID

"fact"

SubChunk2Size

0x4 0x0 0x0 0x0

NumOfSamples

S0 S1 S2 S3

SubChunk3ID

"data"

SubChunk3Size

D0 D1 D2 D3

Data size (File Size-60)

Block1

256

First ADPCM block

316

. . .

More ADPCM data blocks

If we have n audio blocks, the values in the table are as follows:

F = n × 256 + 52

R = Fs (see Chapter 9.4.1 to see how to calculate Fs)

B =

Fs×256

505

S = n × 505

. D = n × 256

If you know beforehand how much you are going to record, you may ﬁll in the complete header

before any actual data. However, if you don’t know how much you are going to record, you have

to ﬁll in the header size datas F , S and D after ﬁnishing recording.

The 128 words (256 bytes) of an ADPCM block are read from SCI_HDAT0 and written into ﬁle

as follows. The high 8 bits of SCI_HDAT0 should be written as the ﬁrst byte to a ﬁle, then the

low 8 bits. Note that this is contrary to the default operation of some 16-bit microcontrollers,

and you may have to take extra care to do this right.

Version: 1.09, 2018-03-16

VS1003 bảng dữ liệu(PDF) 39 Page - VLSI Solution Oy

VS1003 bảng dữ liệu(HTML) 39 Page - VLSI Solution Oy

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

bảng dữ liệu tải về

Link URL