Integrated Circuits Inc.

aP8942A

Ver 2.1

APR, 2007

5

VOICE SECTION COMBINATIONS

Voice files created by the PC base developing system are stored in the built-in EPROM of the

aP8942A chip as a number of fixed length Voice Blocks.

Voice Blocks are then selected and

grouped into Voice Groups for playback.

Up to 32 Voice Groups are allowed.

A Voice Block

Table is used to store the information of combinations of Voice Blocks and then group them

together to form Voice Group.

Chip

aP8942A

Memory size

1M bits

Max no. of Voice Block

252

No. of bytes per Voice Block

512

Max. no. of Voice Group

32

No. of Voice Table entries

960

Voice Length (@ 6KHz 4-bit ADPCM)

42 sec

Example of Voice Block Combination

Assume here we have three voice files, they are “How are You?”, Sound Effect and Music.

Each

of the voice file is divided into a number of fixed length Voice Block and stored into the memory.

Voice File 1 - “How are You?” is stored in Voice Block B0 to B12.

Voice File 2 - Sound Effect is stored in Voice Block B13 to B15.

Voice File 3 - Music is Voice Block B16 to B40.

Voice Blocks are grouped together using Voice Table to form Voice Group for playback:

Group no.

Voice Group contents

Voice Table Entries

Group 1

“How are You?”

B0 … B12

Group 2

Sound Effect + “How are You?”

B13 … B15 + B0 … B12

Group 3

“How are You?” + Music

B0 … B12 + B16 … B40

Group 4

Music

B16 … B40

Voice Data Compression

Voice File data is stored in the on-chip EPROM as either 4-bit ADPCM or 8-bit PCM format.

Voice data stored as 4-bit ADPCM provides 2:1 data compression which can save 50% of memory

space.

On the other hand, voice data are stored as 8-bit PCM format means no data compression is

employed but voice playback quality will be better.