| 摘要 |
PURPOSE:To shorten the writing time and to increase the data assuring period, by providing an ROM which is capable of electric writing and erasion with irradiation of ultraviolet rays and another ROM which is capable of electric writing and erasion on a chip. CONSTITUTION:An EEPROM part I which is capable of electric writing and erasion and an EPROM part II which is capable of electric writing and erasion with irradiation of ultraviolet rays are provided on a chip. When the part I is used, a drain 2 of the part I is connected to a sense amplifier V via a selecting circuit III and a source 21 is earthed respectively. When the part II is used, the source 21 of the part II is connected to the amplifier V via the circuit III and the drain is cut off respectively. Thus an ROM which simplifies the development of a program with the expanding performance and has the data assuring period enough. |
