FIELD: non-volatile semiconductor memory units. SUBSTANCE: device has multiple memory gates designed as floating gates, through voltage generator which is used for writing to selected memory locations and writing voltage generator, which is used for testing of successful storage of chosen memory location. High-voltage generator is used for generation of writing voltage. Tuning circuit is used for detection of writing voltage level in order to increase writing voltage in stepwise mode within given voltage range each time when chosen memory locations fail to be programmed. Comparison circuit is used for comparison of specific voltage level to reference voltage in order to produce comparison signal. Circuit for control of high-voltage generation is used for triggering high- voltage generator in response to comparison signal. EFFECT: possibility to keep uniform threshold voltage of programmed memory location. 8 cl, 13 dwg
