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US 7,890,721 B2Granted
Implementation of integrated status of a protection register word in a protection register array
AssigneeAtmel Corporation
InventorJung Y. Lee
Life of this patent
Estimating the term…
Abstract
A protection register array in which the lock status of the protection register is stored outside of the array. An initial verify function is used to read lock status.
Claims15
An electronic device comprising:
- a memory device having a memory array with memory cells grouped in erase blocks such that data in the memory cells can be erased on a block basis;
- a protection register array in the memory device, the protection register array including:
- a plurality of protection registers, each of the protection registers having a plurality of bit locations and an address in the memory device, a protection register being a storage area in the memory device that is separate from the erase blocks;
- and
- a set of bit locations in the protection register array arranged to store a lock status word, the lock status word being a multiple bit word including an individual lock status for each of the protection registers, the set of bit locations accessible in the memory device at an access address, the access address being a single address for the lock status word, the access address of the lock status word being different from the address of each protection register;
- and
- a circuit that stores and operatively accesses a lock status in the lock status word such that the circuit operatively determines a lock status of a specified protection register of the plurality of protection registers prior to applying a program pulse of a command sequence for operating on the protection register array, the command sequence including an address of the specified protection register of the plurality of programmable registers such that the circuit operatively matches the address of the specified protection register to a corresponding bit in the lock status word decoded from a verify function applied to read the lock status word at the single access address prior to applying the program pulse.
4 more elements
A process comprising:
- determining a lock status for a protection register in a protection register array in a memory device, the memory device having a memory array with memory cells grouped in erase blocks such that data in the memory cells can be erased on a block basis, a protection register being a storage area of the memory device that is separate from the erase blocks, the protection register array having a plurality of protection registers, the lock status being stored in a lock status word in the protection register array, the lock status word being a multiple bit word including an individual lock status for each of the protection registers, the lock status word being accessed at a single access address for the lock status word, the determination including:
- prior to applying a program pulse of a command sequence for operating on the protection register array, the command sequence including an address of a specified protection register of the plurality of registers, initiating a read of the lock status word at the single access address first upon receiving the command sequence, the single access address being different from the address of the specified protection register in the command sequence;
- reading the lock status word at the single access address with said read effected using an initial verify function providing the lock status word as latched data;
- decoding the latched data from said verify function reading the lock status word at the single access address;
- and
- matching the address of the specified protection register to a corresponding bit in said latched data to determine the lock status of the specified protection register.
3 more elements
A process comprising:
- determining a lock status of a protection register of a plurality of programmable protection registers in a protection register array in a memory device, the memory device having a memory array with memory cells grouped in erase blocks such that data in the memory cells can be erased on a block basis, a protection register being a storage area of the memory device that is separate from the erase blocks, the protection register array including a first protection register in addition to the plurality of programmable protection registers, the first protection register containing an A block and a B block, said A block programmed by a manufacturer, the lock status being stored in a lock status word in the protection register array, the lock status word being a multiple bit word including an individual lock status for each of the programmable protection registers, the lock status word being accessed at a single access address for the lock status word, the determination including:
- prior to applying a program pulse of a command sequence for operating on the protection register array, the command sequence including an address of a specified protection register of the plurality of programmable protection registers, initiating a read of the lock status word at the single access address first upon receiving the command sequence, the single access address being different from the address of the specified protection register in the command sequence such that the single address is checked to determine whether it is protected;
- if the single access address in not protected, reading the lock status word at the single access address with said read effected using an initial verify function providing the lock status word as latched data;
- decoding the latched data from said verify function reading the lock status word at the single access address;
- and
- matching the address of the specified protection register to a corresponding bit in said latched data to determine the lock status of the specified protection register.
3 more elements
Dependencies are inferred from the claim text.