Semiconductor storage device having a user region and a redundancy region
The present invention provides a semiconductor storage device that requires no specialized circuit or the like for reading redundancy data from a redundancy region, and that is capable of freely changing the arrangement of the redundancy region in the memory array area. A semiconductor storage device of the present invention includes a memory array configured as shown below. The memory array includes a user region which is composed of given page units and where user data is stored, and a redundancy region which is composed of the same given page units and where redundancy data is stored. The area in the memory array can be used either as the user region or as the redundancy region.
1. A semiconductor storage device comprising a memory array, said memory array comprising:
a user region where user data is stored; and
a redundancy region where redundancy data is stored,
wherein said user region and said redundancy region are each formed of at least one entire given page unit and each page unit in said memory array can be used either as said user region or as said redundancy region.
2. The semiconductor storage device according to claim 1 , further comprising:
an I/O portion that receives, from outside, a read command that contains information about a user address indicating an address in said user region where a specified piece of said user data is stored, and information about a redundancy address indicating an address in said redundancy region where a piece of said redundancy data that corresponds to said specified piece of user data is stored; and
a controller that reads said specified piece of user data from said user region on the basis of said information about said user address, and that reads said piece of redundancy data that corresponds to said specified piece of user data from said redundancy region on the basis of said information about said redundancy address.
3. The semiconductor storage device according to claim 2 ,
wherein said information about said redundancy address is an address value or an index value used in relative addressing, said semiconductor storage device further comprises a redundancy address offset register that is capable of setting an offset value, and
said controller reads said specified piece of redundancy data from said redundancy region on the basis of said address value or said index value and said offset value set in said redundancy address offset register.
4. The semiconductor storage device according to claim 3 , wherein said redundancy address offset register is capable of setting said offset value through an operation of external equipment.
5. The semiconductor storage device according to claim 2 , wherein
said information about said redundancy address indicates a variation from a previous address, and
said controller specifies a current address on the basis of the variation from said previous address and reads said piece of redundancy data that corresponds to said specified piece of user data from said redundancy region on the basis of the specified current address.
6. The semiconductor storage device according to claim 2 , wherein
said information about said redundancy address indicates a given expression for calculation, and
said controller specifies the address on the basis of said given expression for calculation and reads said piece of redundancy data that corresponds to said specified piece of user data from said redundancy region on the basis of the specified address.
7. The semiconductor storage device according to claim 1 , further comprising a redundancy data storing register capable of temporarily storing said redundancy data read from said redundancy region.