Abstract: Methods and circuits for reducing unnecessary changes to outputs of latch circuits are provided. Unnecessary changes to outputs of latch circuits may be reduced by preventing the outputs of the latch circuits from changing when an invalid command is detected. For some embodiments, an invalid command detector is provided that generates an invalid command signal used to inhibit latch circuits, in response to detecting an invalid command.

Abstract: A column access system is provided with a column counter for producing a column address in response to an external address. The column address is latched in an address decoder which decodes the column address to select a column in the DRAM. A command decoder generates a column decode enable signal supplied to the address decoder to control latching of the column address, and a write enable signal, together with data, supplied to a write driver. A data latch is provided in the write driver for latching data until an equalize control signal is activated. The latched data signal drives global input/output pair to provide data writing to the DRAM.

Abstract: A memory having a SRAM, a DRAM, and two independent and functionally identical IO ports. Each port may be used as a read-only, a write-only, or a read-write port. One port may perform a read access to the SRAM, whereas the other port may carry out a write access to the SRAM in the same clock cycle. Each and every location of the SRAM may be accessed from any of the ports. Each port comprises a two-stage pipelined data path for providing a read or write access to the SRAM. Stage 1 decodes control and write enable signals, latches address signals and performs the output of read data. Stage 2 supports accesses to SRAM cells for writing and reading data. In a unified-port mode of operation, two 16-bit ports may be combined to produce a single port supporting a 32-bit write or read access to the SRAM. In a data burst mode of operation, each port may be programmed to select individual length of data bursts and individual burst type.

Abstract: A multi-port RAM (MPRAM) having a SRAM and a DRAM. A global bus is arranged between the DRAM and the SRAM to provide bi-directional transfer of 256-bit data blocks between the SRAM and the DRAM. Two independent input/output ports are coupled to the SRAM to enable a user to write or read data to or from the SRAM and DRAM. Byte masking is provided for each of the ports to mask bytes of data supplied to the MPRAM. A write-per-bit (WPB) mask register is arranged between the ports and the SRAM to prevent unnecessary bits of input data from being written into the SRAM. A byte write enable (BWE) mask register is arranged between the SRAM and the DRAM to prevent unnecessary bytes of data from being transferred from the SRAM to the DRAM. Each of the mask registers may be loaded with mask data from both of the ports concurrently, or from any one of them.

Abstract: A multi-port memory chip having a DRAM main memory and a SRAM cache memory coupled via a global bus. An addressing system enables the user to perform data transfers between external data ports and the SRAM concurrently with data transfers between the DRAM and the SRAM. To support DRAM operations, DRAM address pins on the memory chip select a data block in the DRAM, and indicates a SRAM line for receiving or transferring data. To support SRAM operations, SRAM address pins determine addressed line and word in the SRAM. To reduce the number of pins on the memory chip the DRAM address pins and SRAM address pins are used for supplying commands that define various memory operations.

Abstract: One embodiment of an apparatus for generating a boosted voltage to drive a data signal comprises a voltage pump that includes a driver coupled to an input signal for generating the boosted voltage signal from the input signal; a capacitor coupled to the data signal that stores a charge thereof; and an output transistor that delivers an incremental charge to the driver when the drive signal is asserted. Thus, the boosted voltage signal compensates for a change in logic level of the drive signal. In another embodiment, the apparatus also has gates for combining a plurality of data signals into a single disable-on-low signal. The disable-on-low signal is coupled to the output transistor. When all the data signals are at a low logic level, the disable-on-low signal turns off the output transistor, disabling the circuit. As a result, the circuit conserves power by generating the boosted voltage signal only when needed.

Abstract: An amplifier of a type having complementary output nodes in a data output mode of operation. When an external output enable signal is at a low level, the amplifier is enabled to output a data signal. When the output enable signal is set into a high level, the amplifier is brought into an output disable mode, in which both of its output nodes are set to a low level. The amplifier contains logic circuitry for supplying the output nodes with the data signal and output enable signal. In the output disable mode, a shunting circuit is arranged between the output nodes to provide two discharge paths for a charge stored at one of the output nodes when the signal at this output node transfers from a high level to a low level.

Abstract: An apparatus for driving a bitline driver of a memory array is disclosed. The memory array has row lines, complementary pairs of bitlines driven by bitline drivers, and memory cells at the intersections of the bitlines and the row lines. First and second complementary write data lines provide a bit to be written to the driver and a complement of the bit. A source of a boosted voltage is coupled to a level shifter that conducts the boosted voltage to the bitline driver when the write enable line and the first write data line are asserted. The data bit is latched through a bistable latch to the bitline driver when the write enable line is asserted. A method of driving a bitline of a memory array involves receiving a data bit to be written to the bitline and a complement of the data bit; boosting one of the data bits to a voltage of a magnitude greater than a supply voltage of the memory array; and driving the data bit to a bitline driver.