| 摘要 |
PURPOSE:To enable a user to change optionally the chip selection information by using a programmable memory circuit which can set the optional information and deciding the chip selection signal based on the set information. CONSTITUTION:Nonvolatile semiconductor memory elements 11-13 which supply the signals S0, S1 and S2 to a gate from an input terminal for chip selec tion information are connected in series to load MISFETs 14-16 to which a reference power supply VDD is applied. Then the memory outputs T0, T1 and T2 extracted from contacts X1-X3 and those information S0-S2 are sup plied to exclusive OR circuits 17-10 respectively. A selection signal S is delivered from a NOR circuit 20. The states of elements 11-13 can be changed to optional forms in response to chip selection information. Thus it is possible to change the device selecting information without changing all semiconductor devices. |
