1
P/N:PM0426
REV. 2.2, JAN 20, 1998
ALL DIGITAL VOICE RECORDER MACHINE
BASED ON THE MX93521 VOCODER CHIP
1. FEATURES
Excellent sound quality by adopting 4800bps CELP
speech compression alogorithm.
Silent Compression algorithm to further compress si
lence between speech.
Flash Memory Management alogorithm to manage
down-graded Flash Memory to store compressed
speech data. With silent compression, one 4Mbit flash
memory could store up to 18 minutes speech.
Support 4/8/16/32 Mbit Samsung Flash Memory or its
compatible parts
Support both parallel and serial microprocessor inter
face.
Codec Interface circuit (support both TP3054 and
MX93000)
Host controllable LCD Module Interface
2.GENERAL DESCRIPTION
This document describes how to implement an all-digital voice recorder using the MX93521 chip. The MX93521 is a
Digital Recorder Data Pump which is controlled by an external microprocessor to perform various recorder function.
The MX93521 is fully controlled by a HOST controller through a simple HOST interface protocol. The HOST could
initiate many digital recording functions such as record, play, repeat, search, skip, insertion, message managing
and self-diagnosis. Also, HOST could set MX93521 in VOCODER mode and use MX93521 as a speech compres-
sion/decompression data pump. The functions supported by MX93521 are listed as followed.
MODE
FUNCTION PATH
RECORD
CODEC-->(COMPRESS)-->FLASH
PLAY
CODEC-->(DECOMPRESS)<--FLASH
RECORD (VOCODER)
CODEC-->(COMPRESS)-->HOST
PLAY (VOCODER)
CODEC-->(DECOMPRESS)<--HOST
DIRECT CODEC PLAY MODE
CODEC-->(PCM/u-Law)<--HOST
DOWNLOAD MESSAGE
FLASH(MSG)-->HOST
UPLOAD MESSAGE
FLASH(MSG)<--HOST
DATABANK ACCESS
FLASH(DATA)<-- -->HOST
Host writable message header (4 bytes) for identifica
-tion or index purpose
Powerful Editing Function
Varieties of operating function including Rewind, Fast
Forward, Repeat and message editing etc.
Voice activated recording
Use Flash memory to store user data (data bank)
Upload/Download speech message data from/to
HOST
VOCODER mode (VOice COmpressor/
DEcompressoR)
Direct CODEC Play Mode (Play PCM/u-Law data re
ceived from HOST)
Play Voice Prompt from ROM/FLASH memory
DTMF tone genarator
MX93521
PDF 
ZIP
