摘要:
A nonvolatile memory comprises a memory array and a control circuit coupled to the memory array for performing memory operations with respect to the memory array. A storage circuit associated with the memory array is provided for storing a data. When the data is stored in the storage circuit, the memory array is locked from being accessed for the memory operations. A logic circuit is coupled to the control circuit and the storage circuit for preventing the control circuit from accessing the memory array with respect to the memory operations in accordance with the data. The logic circuit prevents the control circuit from accessing the memory array when the storage circuit stores the data. A control input is provided for receiving a control signal. The control signal is applied to the logic circuit and can be in a first voltage state and a second voltage state. When the control signal is in the first voltage state, the logic circuit is enabled to lock the memory array with respect to the memory operations in accordance with the data stored in the storage circuit. When the control signal is in the second voltage state, the logic circuit is disabled to lock the memory array and the memory array is allowed for the memory operations regardless of the data stored in the storage circuit.
摘要:
A method and device for selectively enabling and disabling write access to flash blocks in a flash memory device. A lock command locks and unlocks a flash block in a flash array containing a plurality of flash blocks. A block data row decoder selects a block data area of the flash block, and a block status row decoder selects a block status area of the flash block. A lock bit in the block status area is programmed to a first logic state if the lock command specifies a lock flash block operation, or to a second logic state if the lock command specifies a release flash block operation. If a write protect input, read from the write protect pin of the flash memory device, indicates that a write lock is enabled and if a block enabled status bit in a block status register corresponding to the block indicates that the block has the write lock, then the lock bit is read and stored into the block enabled status bit in the block status register corresponding to the block. The write protect input is read again from the write protect pin and if the write protect input indicates that the write lock is enabled, and if the block enabled status bit in the block status register corresponding to the block, as updated, indicates that the block has the write lock, then an error is signaled.
摘要:
A flash memory device having a page buffer circuit with special testing modes. The page buffer circuit comprises a plane A and a plane B, each comprising a static random access memory array. The page buffer circuit further comprises a mode control circuit that maps the plane A and the plane B as a contiguous extended memory space accessible over a host bus. The page buffer circuit also maps the plane A and the plane B as a control store for a flash array controller of the flash memory device.
摘要:
Circuitry for propagating test mode signals associated with a memory array including a plurality of circuits for storing test mode signals, apparatus for selectively providing test mode data to each of the circuits for storing test mode signals, and apparatus for simultaneously activating all of the circuits for storing test mode signals to provide output signals to be used for testing.
摘要:
A circuit which monitors the internal state of flash memory array programming circuitry and conveys that state to circuitry external to the flash memory array so that external circuitry need not delay during any period in which a programming operation is taking place within the flash memory array.
摘要:
A flash memory device having a page buffer circuit with special testing modes. The page buffer circuit comprises a plane A and a plane B, each comprising a static random access memory array. The page buffer circuit further comprises a mode control circuit that maps the plane A and the plane B as a contiguous extended memory space accessible over a host bus. The page buffer circuit also maps the plane A and the plane B as a control store for a flash array controller of the flash memory device.
摘要:
A circuit for selectively protecting data stored within a range of addresses from programming and erasing. The circuit includes a circuit for generating an active lock signal. The circuit generates an active lock signal when a protect signal is active and an address signal represents an address within the protected range. Both erasure and programming are prevented while the lock signal is active. Programming and erasure of protected data is permitted while the lock signal is inactive. A method for selectively protecting data within a range of addresses on a non-volatile semiconductor memory from programming or erasure is also described.
摘要:
Erase control circuitry for erasing a flash memory array. The erase control circuitry resides on the same substrate as the flash memory array, along with a command state machine. The command state machine recognizes and externally generated erase command applied to the terminals and generates an active erase control signal, to which the erase control circuitry responds. The erase control circuitry includes precondition pulse application circuitry, erase pulse application circuitry and erase verification circuitry. The precondition pulse application circuitry preconditions the array by programming each bit in the flash memory to a threshold voltage level representative of a programmed state. The erase pulse application circuitry applies a single erase pulse at a time to the flash memory array to erase the flash array by bringing the threshold voltage level of each cell in the array to a level representative of an erased state. The erase verification circuitry verifies the erasure of the flash memory array on a byte by byte basis. If the byte currently being verified has been erased; the erase verification circuitry brings a match signal to an active level. The erase control circuitry determines whether additional erase pulses should be applied to the flash array based upon the match signal and the number of erase pulses previously applied to the flash array described is program control circuitry and methods of programming and erasing a flash memory array in response to two step command sequences.
摘要:
A command state machine for control circuitry associated with a memory array which control circuitry includes apparatus for programming and erasing the memory array including first state machine logic apparatus for providing control signals for reading the memory array and for initiating operations of the apparatus for programming and erasing the memory array in response to commands, and second state machine logic apparatus for controlling information derived from the memory array, the first and second state machine logic apparatus being adapted to assume predetermined states in response to any invalid command which have no adverse affect on the memory array or the control circuitry.
摘要:
Circuitry for suspending an automated sequence for a nonvolatile semiconductor memory is described. The circuitry and memory reside on the same substrate. The circuitry includes a circuit for suspending erasure at a predetermined state of the erase sequence when a suspend signal is active and a circuit for resuming erasure at a predetermined state of the erase sequence when the suspend signal goes inactive. A method for suspending automated erasure sequence of a non-volatile semiconductor memory is also described. A suspend signal is received and erasure is suspended after a first erasure step of the erase sequence if suspend signal is active. Erasure resumes at a second erasure step of the erase sequence when the suspend signal goes inactive.