AP89042_15 Datasheet, PDF (5/19 Pages) Aplus Intergrated Circuits – APLUS INTEGRATED CIRCUITS INC

Integrated Circuits Inc.
aP89042
VOICE SECTION COMBINATIONS
Voice files created by the PC base developing system are stored in the built-in EPROM of the
aP89042 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
Memory size
Max no. of Voice Block
No. of bytes per Voice Block
Max. no. of Voice Group
No. of Voice Table entries
Voice Length (@ 6KHz 4-bit ADPCM)
aP89042
1M bits
252
512
32
960
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
Group 1 “How are You?”
Group 2 Sound Effect + “How are You?”
Group 3 “How are You?” + Music
Group 4 Music
Voice Table Entries
B0 … B12
B13 … B15 + B0 … B12
B0 … B12 + B16 … B40
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.
Ver5.0
5
Aug 23, 2010