Abstract: A method of erasing memory cells in a flash memory device that recombines holes trapped in the tunnel oxide (after an erase operation) with electrons passing through the tunnel oxide is disclosed. The method uses an erase operation that over-erases all memory cells undergoing the erase operation. A cell healing operation is performed on the over-erased cells. The healing operation causes electrons to pass through the tunnel oxide and recombine with trapped holes. The recombination substantially reduces the trapped holes within the tunnel oxide without reducing the speed of the erase operation. Moreover, by reducing trapped holes, charge retention, overall performance and endurance of the flash memory cells are substantially increased.

Abstract: An apparatus for and method of memory operation having a memory, a cache containing a plurality of entries with a plurality of the entries to be written to memory, a detector for detecting in the cache the plurality of entries to be written to memory, and a processor for erasing a first portion of the memory to accommodate the plurality of entries to be written to memory and writing to the first portion of the memory the plurality of entries to be written to memory wherein an erase operation is followed by a plurality of sequential write operations.

Abstract: An embodiment of the present invention is disclosed to include a nonvolatile memory system for controlling erase operations performed on a nonvolatile memory array comprised of rows and columns, the nonvolatile memory array stores digital information organized into blocks with each block having one or more sectors of information and each sector having a user data field and an extension field and each sector stored within a row of the memory array. A controller circuit is coupled to a host circuit and is operative to perform erase operations on the nonvolatile memory array, the controller circuit erases an identified sector of information having a particular user data field and a particular extension field wherein the particular user field and the particular extension field are caused to be erased separately.

Abstract: A data processing system is provided with a flash memory including a plurality of blocks and capable of erasing stored data collectively in units of block and a memory control unit for accessing the flash memory, the memory control unit having a control circuit for formatting the flash memory according to a format information for substantially coinciding each cluster serving as a logical unit of memory region of the flash memory with integer ones of the blocks and a control circuit for determining a size and position of each cluster and carrying out access control for erasing, write-in and reading of data of the flash memory according to the size and position of the determined cluster.

Abstract: Provided in the present invention are a high speed and low program voltage nonvolatile memory cell, a programming method for same and a nonvolatile memory array. A nonvolatile memory cell comprises a first gate insulator formed on a surface of a first channel forming semiconductor region adjacent to a source region; a second gate insulator formed on a surface of a second channel forming semiconductor region adjacent to a drain region; a first gate electrode formed on said first gate insulator; and a second gate electrode formed on said second gate insulator wherein the second gate insulator includes a first layer forming a potential barrier at the interface with the second channel forming region; a third layer forming a potential barrier at the interface with the second gate electrode and the second layer between the first and third layers forming a carrier trapping level.

Abstract: A memory device is presented that utilizes isolated storage elements (200) in a floating gate structure, where tunneling holes (404) are used to program the device and tunneling electrons (504) are used to erase the device. Formation of such a device includes forming a thin tunnel dielectric layer (102) that may be less than 3.5 nanometers. When the control gate electrode (204) of the memory device is negatively biased, the thinner tunnel dielectric (102) allows holes to migrate through the tunnel dielectric to positively charge the isolated storage elements (200). When the device is to be erased, the control gate electrode (204) is positively biased, and rather than forcing the holes back across the tunnel dielectric, electrons present in the channel (402) are pulled through the tunnel dielectric where they recombine with the holes in the floating gate such that the stored positive charge is substantially neutralized.

Abstract: The present invention provides a method and device for reduced-pin integrated circuit I/O testing. In this regard, the present invention provides for the testing of an integrated circuit or chip in a manner which is independent of the number of test pins present on the testing device. The method and device of the present invention are realized through an integrated circuit having two test ports: a scannable I/O test port and a Forcing-Measuring test port, and a plurality of switches. The scannable I/O test port is employed for the input and output of, among other things, scannable shift-register latch data which affects the states of the plurality of switches in the integrated circuit. The Forcing-Measuring test port is employed for, among other things, forcing or measuring voltages and currents associated with the I/O circuits under test through the switches to the circuits under test.

Abstract: A testing method which reduces a testing time for a flash memory is proposed.

Abstract: A column register of an integrated circuit memory, notably in EEPROM technology, is utilized in a method of writing a data word of 2p bits in the memory, where p is a non-zero whole number. The method includes the following steps: 1) erasing all the cells of the word; 2) loading 2q data in 2q high-voltage latches (HV1, HV3, HV5, HV7), and loading 2p-2q other data in the 2p-2q low-voltage latches (LV0, LV2, LV4, LV6); and 3) programming 2q cells of the memory (M0, M2, M4, M6) as a function of the data memorized in the 2q high-voltage latches; as well as repeating 2p-q−1 times the following steps: 4) loading, in the 2q high-voltage latches, of 2q other data that were loaded in the 2q low-voltage latches at step 2); and 5) programming 2q other cells of the memory (M1, M3, M5, M7) as a function of the data memorized in the 2q high-voltage latches.

Abstract: This invention is nonvolatile memory that has an ordinary memory cell region wherein ordinary data is stored and an erase information storage memory region wherein the information that shows the status of the erase operation is stored. The erase information storage memory region comprises nonvolatile memory that can store the information even when the power is cut. Preferably, the erase information storage memory region can store erase information in the memory block units in which the erase operation is executed. Further preferably, the erase information storage memory region is able to store erase information for at least the three statuses that are involved in erase operations: erase operation start status, preprogramming end status, and erase operation complete status.

Abstract: A non-volatile semiconductor memory device comprising a memory array, the memory array divided into a plurality of sectors, each sector comprising a plurality of memory cells, which can be electrically erased, and an erase-verify circuit, capable of simultaneously erasing multiple memory sectors. The erase-verify circuit simultaneously erases a plurality memory sectors, and verifies that the memory cells in a selected memory sector of the plurality of memory sectors is erased. When it determines that the selected memory sector is not erased, it again erases the plurality of memory sectors and again verifies whether the selected memory sector is erased. The erasing of the plurality of memory sectors is repeated until it is verified that the memory cells in the selected memory sector is erased.

Abstract: A select gate transistor has a select gate electrode composed of a first-level conductive layer and a second-level conductive layer. The first-level conductive layer has a plurality of contact areas. The second-level conductive layer has its portions removed that are located above the contact areas. Two adjacent select gate electrodes that are adjacent to each other in the column direction are arranged such that the contact areas of one select gate electrode are not opposed to the contact areas of the other select gate electrode. One select gate electrode has its first- and second-level conductive layers removed in their portions that are opposed to the contact areas of the other select gate electrode.

Abstract: A nonvolatile storage device is constructed so as to include a first storage device for storing data and management information thereof, a request receiving device for receiving a request for writing data at the location shown by a logical address, and an information obtaining device for obtaining the physical address corresponding to the logical address through the management information and for obtaining first management information to control the location when the location is used and second management information to control the location which is not yet used.

Abstract: A non-volatile flash memory system counts the occurrences of an event, such as the number of times that individual blocks have been erased and rewritten, by updating a compressed count only once for the occurrence of a large number of such events. A random or pseudo-random number generator outputs a new number in response to individual occurrences of the event, and updates the compressed count when an output of the random number generator matches a predetermined number. The probability of the predetermined number being generated by the random number generator in response to a single event may be varied as the function of some other factor, such as the value of the compressed count, when that provides more useful tracking of the number of events. These techniques also have application to monitoring other types of recurring events in flash memory systems or in other types of electronic systems.

Abstract: In a semiconductor disk wherein a flash memory into which data is rewritten in block unit is employed as a storage medium; a semiconductor disk comprising a data memory in which file data are stored, a substitutive memory which substitutes for blocks of errors in the data memory, an error memory in which error information of the data memory are stored, and a memory controller which reads data out of, writes data into and erases data from the data memory, the substitutive memory and the error memory. Since the write errors of the flash memory can be remedied, the service life of the semiconductor disk can be prolonged.

Abstract: A method of erasing a memory cell that includes a first region and a second region with a channel therebetween and a gate above the channel, and a charge trapping region that contains a first amount of charge. The method includes: applying a voltage across the gate and the first region in accordance with a coarse erase sequence of voltages so that a portion of the first amount of charge is removed from the charge trapping region; and applying a voltage across the gate and the first region in accordance with a fine erase sequence of voltages so that a portion of the first amount of charge is removed from the charge trapping region.

Abstract: An external storage apparatus which incorporates a flash memory arranged to erase data in units of predetermined blocks and which is structured in such a manner that an error which is made when boot data is read is prevented. Boot data is stored in a plurality of different blocks. Moreover, an identification number indicating whether boot data stored in each of the blocks in which boot data has been stored is new or old is stored in each of the blocks. When the external storage apparatus is booted up, latest boot data among boot data stored in the plurality of the different blocks is read in accordance with the identification number. Latest boot data is used to boot the external storage apparatus up. When the external storage apparatus is booted up, whether boot data stored in the plurality of the different blocks is new or old is determined in accordance with the identification number. If old boot data exists, old boot data is rewritten to latest boot data.

Abstract: The present invention enables to complete a data erase of memory cells of a group in a semiconductor storage device where a data erase is uniformly performed to memory cells of a group until all the cell threshold values become below a reference and memory cells having a cell threshold value below a lower limit are supplied with an electric charge. When a production error occurs in such a way that some memory cells in a predetermined position of a group have a lower erase speed, the semiconductor device is formed in such a way that these memory cells have an erase speed higher than an ideal value. When some memory cells of a group have a lower erase speed, an excessive erase is performed in most memory cells of the group requiring electric charge supply, which increase the erase time as a whole.

Abstract: This invention relates to an information processing method and apparatus. A memory for storing information in block units, comprises a data region for storing data in block units and a first and a second region for storing plural block numbers which are numbers assigned to blocks in a data region. Data is written to a block of the data region corresponding to a block number stored in one of the first and second regions, the block number of the block to which data was written is stored in the other of the first and second regions, and the data in the one of the first and second regions is erased. In this way, there is less risk of memory corruption, and data can be read stably.

Abstract: An electrically alterable, non-volatile memory cell has more than two memory states that can be programmed selectively. Programming of the cell is conducted by applying a plurality of programming signals having different characteristics to the cell. The programming signals include at least a first programming signal which programs the cell by a first increment and a subsequent programming signal which programs the cell by a second increment smaller than the first increment. As the cell is being programmed to a selected state, its programming status is verified independently of reference values bounding the memory states. For this purpose, a signal indicative of the programming status (e.g., the cell's bit line signal) is compared with a reference signal corresponding to the selected state but having a value different from the reference value or values bounding the selected state. The programming operation can thus be controlled without actually reading the memory state of the cell.

Abstract: An electrically alterable, non-volatile memory cell has more than two memory states that can be programmed selectively. Programming of the cell is conducted by applying a plurality of programming signals having different characteristics to the cell. The programming signals include at least a first programming signal which programs the cell by a first increment and a subsequent programming signal which programs the cell by a second increment smaller than the first increment. As the cell is being programmed to a selected state, its programming status is verified independently of reference values bounding the memory states. For this purpose, a signal indicative of the programming status (e.g., the cell's bit line signal) is compared with a reference signal corresponding to the selected state but having a value different from the reference value or values bounding the selected state. The programming operation can thus be controlled without actually reading the memory state of the cell.

Abstract: The flash memory device according to the present invention includes an erase control circuit, used as a state machine, having embodied erase algorithm which can prevent flash memory cells from being over-erased. The erase control circuit, first, checks whether or not threshold voltages of selected cells reach a predetermined pre-verify voltage higher than the maximum value of a target threshold voltage range corresponding to the erased state. When at least one of the selected cells has its threshold voltage higher than the pre-verify voltage, a high voltage generator generates a bulk voltage that is increased step by step by a predetermined voltage level. And, when the selected cells all have threshold voltages equal to or less than the pre-verify voltage, the high voltage generator generates a constant bulk voltage. According to this bulk voltage control scheme, the number of flash memory cells over-erased at the erase operation is reduced reducing the total erase time.

Abstract: A column register of an integrated circuit memory, notably in EEPROM technology, is utilized in a method of writing a data word of 2p bits in the memory, where p is a non-zero whole number. The method includes the following steps: 1) erasing all the cells of the word; 2) loading 2q data in 2q high-voltage latches (HV1, HV3, HV5, HV7), and loading 2p−2q other data in the 2p−2q low-voltage latches (LV0, LV2, LV4, LV6); and 3) programming 2q cells of the memory (M0, M2, M4, M6) as a function of the data memorized in the 2q high-voltage latches; as well as repeating 2p−q−1 times the following steps: 4) loading, in the 2q high-voltage latches, of 2q other data that were loaded in the 2q low-voltage latches at step 2); and 5) programming 2q other cells of the memory (M1, M3, M5, M7) as a function of the data memorized in the 2q high-voltage latches.

Abstract: A ramping circuit gradually applies an erasing voltage to a memory cell. Within the ramping circuit an NMOS transistor is disclosed which gradually supplies the erasing voltage to the memory cell in response to an external ramping voltage. The NMOS transistor supplies the erasing voltage until the loss voltage of the transistor limits a maximum erasing voltage that the NMOS transistor can supply. The specification then discloses a PMOS transistor which operates to supply the erasing voltage to the memory cell when the NMOS transistor can no longer do so. The PMOS transistor is connected to control circuitry which keeps the PMOS transistor inactive until the output voltage of the NMOS transistor is limited by its voltage loss.

Abstract: An SRAM that has a column clear function with only three vertical lines and six total lines across a cell and a method of operating that cell and an array of those cells. Instead of two bit lines per port and two access devices per port as in a traditional SRAM cell, one bit line and one access device per port is used. In addition, one additional bit line, one additional word line, and two devices in series are used to perform the column clear operation and complete a write operation. The cell is operated by performing write operations using a two step process. To perform a write, each cell in a row to be written is preset during a first step. Then, each cell that is to have a zero written to it is cleared using the additional bit line and additional word line to address the cells to be cleared. A column of cells may be cleared by enabling all the rows for clearing, then asserting column clear control signals for each of the columns in the array to be cleared.

Abstract: A tunnel oxide film 120, a first polysilicon layer 164, a poly-poly insulating film 132 and a second polysilicon layer 166 are formed on a semiconductor substrate in a memory cell area. After that, with two photo resists 168-S and 168-M as a mask, patterning is performed for the films, a layered product of the films formed according to the photo resist 168-S is taken as a gate electrode of a selection transistor S, and a layered product of the films formed according to the photo resist 168-M is taken as a gate electrode of a memory transistor M.

Abstract: There is disclosed a method of erasing a flash memory device. The present invention implements a dummy recovery operation after a recovery operation for recovering the threshold voltage of an over-erased memory cell is implemented. Therefore, it can reduce the flow of the leakage current through bit lines to thus improve the program characteristic of the device.

Abstract: There is disclosed a multi-step pulse generating circuit and a method of erasing a flash memory cell using the same, which can shorten the erase time for the flash memory and reduce the size of a device, in a way that it stores the information at the time when the suspense command is input during the multi-step pulse erase operation, switches it into a read mode, and resumes the erase operation from the time when the information is stored.

Abstract: The threshold of a number of storage transistors is shifted in steps. After such a step, a collective current through the main current channels of a number of these storage transistors is sensed. The same gate-source voltage is applied to all these transistors during sensing. The collective current indicates whether the threshold of all transistors has been sufficiently shifted. If not, a further threshold shifting step is applied.

Abstract: A semiconductor storage device having a plurality of block-erase type non volatile memory chips classifies the memory chips into memory groups of a number equal to twice the number of buffer memories provided in the storage device and assigns logic sector addresses sequentially to sectors contained in one erase block of each memory group in such a manner that the logic sector addresses are sequenced in series to those in the corresponding erase block of the next succeeding memory group.

Abstract: Information for defining a structure of an address bit arrangement of a ROM portion of layout data is affixed, by means of text data as a discriminator, to a typical ROM cell portion indicating a characteristic of the address bit arrangement. Layout data including the affixed information is read in. ROM coordinate information and the text data are extracted. A ROM definition for generating a mask pattern is generated from the extracted ROM coordinate information based on ROM data. Thus, the layout information generating apparatus extracts the arrangement information and coordinate information of a ROM portion automatically, not manually, to generate a ROM definition, thereby considerably decreasing the number of steps to improve productivity.

Abstract: In accordance with an embodiment of the present invention, a method and apparatus is disclosed for use in a digital system having a host coupled to at least two nonvolatile memory devices. The host stores digital information in the nonvolatile memory devices and reads the stored digital information from the nonvolatile memory devices. The memory devices are organized into blocks of sectors of information. The method is for erasing digital information stored in the blocks of the nonvolatile memory devices and comprises assigning a predetermined number of blocks, in sequential order, to each of the nonvolatile memory devices, each block having a predetermined number of sectors.

Abstract: Provided in the present invention are a high speed and low program voltage nonvolatile memory cell, a programming method for same and a nonvolatile memory array. A nonvolatile memory cell comprises a first gate insulator formed on a surface of a first channel forming semiconductor region adjacent to a source region; a second gate insulator formed on a surface of a second channel forming semiconductor region adjacent to a drain region; a first gate electrode formed on said first gate insulator; and a second gate electrode formed on said second gate insulator wherein the second gate insulator includes a first layer forming a potential barrier at the interface with the second channel forming region; a third layer forming a potential barrier at the interface with the second gate electrode and the second layer between the first and third layers forming a carrier trapping level.

Abstract: A structure and method for implementing an EEPROM using 2-bit non-volatile memory cells. Each memory cell has a first charge trapping region for storing a first bit and a second charge trapping region for storing a second bit. The memory cells are arranged in one or more rows, with a word line coupling the gates of all of the memory cells in each row. Diffusion bit lines couple the first charge trapping region of each memory cell with the second charge trapping region of an adjacent memory cell. When the first charge trapping region of a memory cell is erased, the second charge trapping region of the adjacent memory cell is incidentally erased. This incidental erasure is effectively avoided by: (1) reading the bit stored in the second charge trapping region, (2) writing this bit to a storage device, (3) performing the erase operation, and then (4) restoring the bit from the storage device to the second charge trapping region of the adjacent memory cell.

Abstract: A method of erasing a memory cell that includes a first region and a second region with a channel therebetween that has spillover electrons and a gate above the channel, and a charge trapping region that contains a first amount of charge. The method includes generating neutralizing holes in the substrate, moving the neutralizing holes to the channel and substantially neutralizing the spillover electrons with the neutralizing holes moved to the channel.

Abstract: A flash memory system powered by an external primary voltage source, with the system including an array of flash memory cells arranged in rows and columns, with each of the cells including a source region, a drain region, a channel region intermediate the drain and source region, a floating gate disposed over the channel region and a control gate disposed over the floating gate, with the cells located in one of the array columns having their drains connected to a common bit line and with the cells in one of the rows having their control gates connected to a common word line. The memory system includes a control circuit carrying out read, programming and erase operations. The erase operation is performed by applying a negative voltage to control gate of the cell being erased and a positive voltage to the source of the cells being erased.

Abstract: A potential generating circuit generates two types of erase verify threshold values EVT1 and EVT2. These values satisfy the relationship of EVT2=EVT1+(OEVT−EVTL). OEVT is an over-erase verify threshold value. While the erase verify threshold value is set at EVT2, the lower limit of a threshold voltage distribution after data erase is higher than OEVT. EVTL is the lower limit of the threshold voltage distribution after data erase while the erase verify threshold value is set at EVT1 and is lower than OEVT. The erase verify threshold values EVT1 and EVT2 are switched according to an operation mode. During a write/erase test, for example, the erase verify threshold value is set at EVT2. On the other hand, during the normal operation, the erase verify threshold value is set at EVT1.

Abstract: In one aspect, the present invention provides a method for erasing a semiconductor device that comprises applying a voltage pulse at the source of the semiconductor device and a multiple step voltage pulse of the opposite polarity at the gate of the semiconductor device. The multiple step voltage pulse comprises at least a first voltage pulse and a second voltage pulse at the gate of the semiconductor device. The second voltage pulse is usually greater in magnitude than the first voltage pulse. In another aspect, the present invention provides a method for erasing a semiconductor device that comprises applying a substantially constant positive voltage pulse for a first time interval, t1, at the source of the semiconductor device. A first and then a second negative voltage pulse are also applied at the gate of the semiconductor device for a second and third time interval, t2 and t3, respectively. The second negative voltage pulse is greater in magnitude than the first negative voltage pulse.

Abstract: A method and apparatus for providing a charge pump that is particularly useful for generating high voltages and high currents for erasing and programming flash electrically-erasable programmable read only memory arrays (Flash EEPROMs). The invention includes an efficient method and circuit for generating a pumped voltage with no voltage drop from one stage to the next by using a simple two-phase clocking scheme and an auxiliary pump to gate a larger primary pump. One feature allows adjustment of the level of voltage pumping to accommodate higher voltage power supplies.

Abstract: A data input/output circuit used to program the cells of a memory array or to determine the state of those cells. The circuit includes a data write path used for programming the memory cells in the array and a data read path for reading data indicative of the state of the cells. The data write path includes switching means for electrically disconnecting the high capacitance elements of the write path from the read path. The switching means is under the control of a control means which acts to enable or disable the switching means. The switching means serves to electrically isolate the high capacitance elements of the write path from the read path, thereby increasing the speed with which a read operation be performed.

Abstract: A flash Electrically-Erasable Programmable Read-Only Memory (EEPROM) includes a plurality of field effect transistor memory cells, a power supply, and a controller which cooperates with the power supply to apply an erase pulse to the cells, and then erase verify a first byte of cells in each sector. If the first bytes in any sector has not passed erase verify, another erase pulse is applied to the cells of those sectors, and the first byte in each sector which did not pass erase verify the first time is erase verified again. This procedure is continued until the first byte in each sector has passed erase verify. Then, the sectors are processed in sequence to erase and erase verify every cell. First, an erase pulse is applied to all of the cells in the sector. Then, the first byte is erase verified. If the first byte passes erase verify (which it will because it did previously), the next byte is erase verified.

Abstract: A pre-erase/incremented erase mechanism is employed to reduce excessive tunnel oxide fields in flash memory cells. A variable conditioning signal removes charge from “fast” bits in the array, so that they are configured to have threshold voltages closer to an ideal initial state in preparation for an erase cycle. In this manner, the voltage thresholds are tightened and equalized, so that over-erasure problems associated with Fowler-Nordheim tunneling erase operations are substantially reduced, and endurance cycles for the array are maximized. The invention can be used in a device in the field, or as part of a design process for a flash memory cell to evaluate device performance.

Abstract: A method and apparatus manages data and reads code from a nonvolatile writeable memory. In a nonvolatile writeable system, interrupts are disabled. A non-read operation is initiated in the nonvolatile writeable memory. A check for whether an interrupt has occurred is performed. If an interrupt has occurred, then the non-read operation in the nonvolatile writeable memory is suspended. Interrupts are enabled, and code is read from the nonvolatile writeable memory. Non-read operations may include program operations and erase operations.

Abstract: An error detection system for an array of data elements is disclosed. In this system, each data element in the array includes first and second error detection fields. As the system traverses the array, a detecting mechanism sequentially compares the first error detection field with the second error detection field for each data element in order to determine whether the data element is corrupt. The detecting mechanism also compares the first error detection field of adjacent data elements in order to identify duplicates. If an invalid element (i.e. corrupt or a duplicate) is detected, the system then removes or deletes the element from the array.

Abstract: An associative memory contains cells that are formed of a series circuit of an ordinary PMOS transistor with a PMOS transistor with a floating gate. The ordinary PMOS transistor receives of an input vector and the gate of the second PMOS transistor is connected to a learning input. For the associative access, a second vector can be applied to the drain terminal of the second PMOS transistor and, upon readout, the current flow through the respective series circuit is evaluated column-by-column by current evaluator circuits.

Abstract: A system of Flash EEprom memory chips with controlling circuits serves as non-volatile memory such as that provided by magnetic disk drives. Improvements include selective multiple sector erase, in which any combinations of Flash sectors may be erased together. Selective sectors among the selected combination may also be de-selected during the erase operation. Another improvement is the ability to remap and replace defective cells with substitute cells. The remapping is performed automatically as soon as a defective cell is detected. When the number of defects in a Flash sector becomes large, the whole sector is remapped. Yet another improvement is the use of a write cache to reduce the number of writes to the Flash EEprom memory, thereby minimizing the stress to the device from undergoing too many write/erase cycling.

Abstract: A non-volatile semiconductor memory device includes memory cell blocks in which n sectors for erasing are defined where n is an integer equal to or greater than 1. Each of the memory cell blocks includes sense amplifiers, and an activation signal generating circuit activating an activation signal for generating the sense amplifiers. Data held in the sense amplifiers of the memory cell blocks are continuously output in accordance with a burst length. Sectors related to blocks corresponding to the burst length are sequentially subjected to an erase operation.

Abstract: The present invention enables a high-speed processing. The present invention provides a memory management method for a memory having a storage area divided into a plurality of blocks, so that a data in each of the blocks is erased at once when the block is initialized, wherein each of the blocks has a flag indicating a block use state; wherein when erasing a data written in a block, instead of executing an initialization of the block, an erase flag of the block is set to an erase state indicating that a data contained in the block is to be erased; and wherein prior to writing a new data in a block having the erase flag in the erase state, the initialization processing is executed to the block, setting the flag of the block to an initial state.

Abstract: Memory devices having 1-transistor flash memory cells that in one embodiment allows bit-by-bit erase and in other embodiments allows erase of a multi-bit word. The word can be 8 bits, 16 bits, 32 bits, 64 bits or any size word. The memory devices have source bitlines that are connected to the bitline driver that controls the bitlines. The bitline driver and a wordline driver controls the voltages applied to selected bitlines, source bitlines while the wordline driver controls the voltage applied to selected wordlines to allow selected memory cells to be programmed, erased, or read.

Abstract: In accordance with an embodiment of the present invention, a method and apparatus is disclosed for use in a digital system having a host coupled to at least two nonvolatile memory devices. The host stores digital information in the nonvolatile memory devices and reads the stored digital information from the nonvolatile memory devices. The memory devices are organized into blocks of sectors of information. The method is for erasing digital information stored in the blocks of the nonvolatile memory devices and comprises assigning a predetermined number of blocks, in sequential order, to each of the nonvolatile memory devices, each block having a predetermined number of sectors.