Patent ID: 6594777
Filing Date: 2003-07-15
Classification: G06F,G11C,Y02D

Abstract:
A semiconductor memory device, comprising:a read-only semiconductor memory device; and a nonvolatile semiconductor memory device for replacing defective data in at least one defective region which occurred in the read-only semiconductor memory device with modification data for modifying the defective data, the nonvolatile semiconductor memory device comprising: a memory section capable of electrically writing address data indicating an address of the defective region, and the modification data; and an address determination circuit for outputting a determination result signal which inactivates the read-only semiconductor memory device when the address data matches an address provided from outside the semiconductor memory device, wherein data is not read from the read-only semiconductor memory device when the address data matches the address; wherein the nonvolatile semiconductor memory device reads and outputs the modification data from the memory section when the address data matches the address.