Non-volatile multi-state memory device capable with variable storing

Abstract

This non-volatile multi-state memory device switches a storing resolution of multi-state data corresponding to digital data stored in a non-volatile memory cell according to the data's characteristics. In more detail, digital audio data are output from an ADPCM encoder in n-bit units and m bits of address data indicating an address at which audio data are stored are output from an address controller. These are then input to a switching circuit, a bit number converting circuit converts m bits of address data to n bits of address data at the same level as the m bit data, and the converted n bits of address data and n bits of audio data are inputted to a second multiplexer. An output of the Second multiplexer is then selected in compliance with a switch signal from the address controller and either the selected n bits of address data or the audio data are sent to a read-write circuit. Consequently, for example, writing is carried out with storing resolution deemed as 16 when 4 bits of audio data are stored in an EEPROM cell array and storing resolution deemed as 2 when for instance 1 bit of address data is stored.