A 64-min single-chip voice recorder/player using embedded 4-b/cell flash memory

A system-on-chip prototype implementing a full integration of a 64-minutes digital voice recorder/player and embedding a 4-b/cell multilevel digital f lash memory is presented in this paper. A hardwired adaptive-differential p ulse-code modulation speech coder/decoder (8 to 40 kb/s) and a microcontrol ler are integrated into a bus-centric architecture. An 8-cell/32-Mb multile vel flash memory is used as an embedded mass storage media and a fully digi tal on-chip built-in-self-test solution is presented. This speech recording system features a modular architecture allowing full reuse and mix-and-match of its IP building blocks. The architecture of the system and solutions for implementing embedded multilevel flash memories ar e presented. System operation modes are described shelving how the desired message editing functionality is implemented by a mixed hardware/software s olution. The chip is 3-V-only and it counts 13 M transistors at 225 mm(2) a rea in a 0.5-mum embedded flash technology.