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 compression/decompression data pump. The functions supported by MX93521 are listed as followed.

FEATURES
• Excellent sound quality by adopting 4800bps CELP
   speech compression alogorithm.
• Silent Compression algorithm to further compress silence 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 interface.
• Codec Interface circuit (support both TP3054 and MX93000)
• Host controllable LCD Module Interface
• Host writable message header (4 bytes) for identification 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/toHOST
• VOCODER mode (VOice COmpressor/DEcompressoR)
• Direct CODEC Play Mode (Play PCM/u-Law data received from HOST)
• Play Voice Prompt from ROM/FLASH memory
• DTMF tone genarator