Abstract: 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.

Abstract: A control circuit for a computer component circuit which includes oscillator apparatus for providing square wave pulses at a prescribed frequency, gating apparatus for providing the square wave pulses at an output terminal for use as a clock for the component circuit, timing apparatus for sensing a period during which the component circuit has not performed an operation, and apparatus for disabling the gating apparatus for providing the square wave pulses at an output terminal.

Abstract: 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.

Abstract: Circuitry for programming a non-volatile semiconductor memory is described. The circuitry includes a circuit for enabling the non-volatile semiconductor memory to program a bit of the non-volatile semiconductor memory. The enabling circuit causes the bit to be programmed according to a pattern bit. The circuitry also includes a second enabling circuit, which enables the non-volatile semiconductor memory to verify the programming of the bit. Circuitry for erasing a non-volatile semiconductor memory is disclosed. A method for programming a nonvolatile semiconductor memory is also described.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A status register in a non-volatile semiconductor memory is described. The status register outputs to pins of the non-volatile semiconductor memory a number of signals that indicate the status of program and erase operations performed on the memory array of the non-volatile semiconductor memory. The status register includes a clock circuit that generates a clock signal in response to an output enable signal. The clock signal is coupled to a pair of latches that respond by coupling their signals to the pins. One latch couples an erase fail signal to a pin to indicate whether the memory array has been sucessfully erased. The other latch couples a program fail signal to a pin to indicate whether an addressed memory cell of the memory array has been sucessfully programmed.

Abstract: 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.

Abstract: A method for writing data to an entry in a portion of a flash EEPROM memory array during a period in which that portion of the array is being erased and writing is prohibited. The method includes writing the data to a new entry position apart from the portion of the array which is being erased along with a revision number which is greater than the revision number of the original data in the original portion of the array, writing of the busy condition of the original entry to a temporary storage position apart from the portion of the array which is being erased, and invalidating entries listed in the temporary storage position when the erase operation is concluded.

Abstract: An arrangement for generating signals for generating a particular set of test conditions within a digital circuit including a plurality of latches for storing individual bits of data representing individual operations to be accomplished within the digital circuitry, the latches each having input and output terminals; the output terminals of each of the latches being connected to individual portions of the digital circuitry to effect an individual operation thereby; apparatus connected to the input terminals of the latches for setting individual selected ones of the latches to provide selected test conditions; and apparatus for transferring the condition of a selected number of the latches simultaneously to effect a selected test condition.

Abstract: A blocking architecture for use in non-volatile semiconductor memories is disclosed. This architecture minimizes device area taken up by signal lines while maximizing device yield. Additionally, this architecture minimizes the Y decoding mechanism while maximizing device performance.

Abstract: 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.

Abstract: A semiconductor flash EPROM/EEPROM device which includes a command port controller for receiving command instructions from a data bus coupled to the memory device. Instruction words to a command port controller operates to instruct the device to perform read, erase, program, or verify functions and the command port controller generates necessary control signals to cause the memory to function appropriately. By utilizing the command port controller the memory device can be erased and programmed while the device is in the circuit and permits pin compatibility with the prior art EPROM and EEPROMs.

Abstract: A non-volatile memory is described. The memory includes a memory array that includes a main block and a boot block. The memory also includes a control input for receiving a control signal. The control signal can be in a first voltage state, a second voltage state, and a third voltage state. Circuitry means is coupled to receive the control signal at the control input for (1) allowing the boot block to be updated when the control signal is in the first state and for (2) generating a power off signal to switch the memory into a substantially powered off state when the control signal is in the third voltage state. A method of controlling a non-volatile memory is also described.

Abstract: A semiconductor flash EPROM/EEPROM device which includes a command port for receiving instruction on a data line and providing control signals to a memory for providing program and erase functions, a method to program and erase the memory. A program sequence is comprised of setting up a program command during a first write cycle, preforming a second write cycle to load address to address register and data to to a data register, programming during a program cycle and writing a program verify command during a third write cycle to verify the programmed data during a read cycle. An erase sequence is comprised of writing a setup erase command during a first write cycle, an erase command during a second write cycle providing the erasure during an erase cycle, writing the erase verify command during a third write cycle which also addresses the address of the memory and providing erase verification during a read cycle. Both the erase and program cycles provide for measured incremental erasing and programming.