Abstract:
An apparatus is provided for precharging a conductor within a bus containing a plurality of conductors. The apparatus comprises a precharge driver which precharges alternating pairs of conductors to opposite rail voltages. By precharging pairs of conductors to alternating rails, the present apparatus can minimize the speed degradation problems associated with a transitioning target conductor within the bus. Precharging alternating pairs of conductors also minimizes crosstalk noise from transitioning neighbor conductors to a non-transitioning target conductor. The improved dynamic bus thereby demonstrates improvements in speed degradation and crosstalk noise as seen by a transitioning target conductor or non-transitioning target conductor, respectively.
Abstract:
A voltage booster circuit includes a driver circuit (117) for generating a 3-state output for driving wordlines via row decoder circuits in an array of flash EEPROM memory cells during read and programming modes of operation. The driver circuit effectively disconnects a large booster capacitor (115) in order to allow a small charge pump (114) to further pump up the wordline voltage during programming. As a result, the booster pump has improved efficiency since there is achieved a significant reduction in power consumption.
Abstract:
A memory cell for a programmable logic device (PLD) and method for programming the memory cell. The memory cell includes components typically found in a memory cell for a PLD including an NMOS transistor having a floating gate, and two capacitors coupled to the floating gate, one capacitor being a tunneling capacitor enabling charge to be added to and removed from the floating gate. The memory cell further includes an NMOS pass gate transistor for supplying charge to the tunneling capacitor, but unlike conventional NMOS pass gates, it has a reduced threshold so that during programming when a programming voltage is applied to its drain, it can be turned on with an identical programming voltage applied to its gate, rather than requiring that its gate voltage be pumped above its drain voltage during programming. The reduced threshold can be obtained by removing the vt implant and punch through implant normally provided in its channel, or by other means.
Abstract:
An ATM switch with multicast capability uses a feedback mechanism for resolving contentions. A multicast network reads N cells from an input queue, replicates multicast cells and translates their addresses in accordance with an external look-up table. The processed N cells are stored in a temporary buffer until information regarding the number (F) of cells fed back due to contention in the previous switching cycle is available. A rotator positions N-F cells from the temporary buffer on inputs of an output network so as to assign the cells from the temporary buffer a lower priority than a priority of the feed back cells. The output network selects the cells that can be switched to their destinations and transfers them to output ports. The cells that cannot be switched due to contention are fed back to be presented for the output network consideration in the next switching cycle. At the same time, a pointer of the input queue is decremented by a factor depending on the number of feedback cells, and the number of multicast and unicast cells in the current switching cycle.
Abstract:
A digital signal controller is provided having modular operation. Specifically, the digital signal controller includes a sequence control unit and a sequencer for producing a sequence of macro instructions and a sequence of micro instructions, respectively. Changes in the number or order of macro instructions may not require changes to the number and order of micro instructions and vice versa. As such, changes in macro instructions can occur by modifying the sequence control unit and possibly the decoder without necessarily changing the sequencer. Changes in the number and order of micro instructions require changes in the sequencer and possibly the decoder without necessarily changing the sequence control unit. The aforementioned modular technique of forwarding macro and micro instructions to a decoder for controlling an execution unit arranged between an analog interface unit and a DSP allows variability in the operation of the DSP, as well as variability in the design implementation of changes to the digital signal controller.
Abstract:
An instruction decoder (220) includes an emulation code sequencer (510) and emulation code ROM (520) for handling various instructions. The emulation code ROM includes a sequence of operations (Op) and an operation sequencing control code (OpSeq). Branch instructions such as conditional branch instructions may be encoded into the emulation code ROM so that a second branch, in combination with the branching operation controlled by the OpSeq code, is applied to an operation code sequence. Two-way branching permits flexible branching to locations within the emulation code ROM so that memory capacity is conserved. A superscalar microprocessor (120) includes an instruction decoder having an emulation code control circuit and an emulation ROM which emulates the function of a logic instruction decoder. The emulation code ROM is arranged as a matrix of multiple-operation (Op) units with each multiple-Op unit including a control field that points to a next location in the emulation code ROM. In one embodiment, the emulation code ROM is arranged to include a plurality of four-Op units, called Op quads, with each Op quad including a sequencing control field, called an OpSeq field.
Abstract:
Submicron contacts/vias and trenches are provided in a dielectric layer by forming an opening having an initial dimension and reducing the initial dimension by depositing a second dielectric material in the opening.
Abstract:
A flow control enabled Ethernet switch that applies backpressure to input ports that attempt to transmit a data packet to a busy destination port. The backpressure is a phantom packet that activates the IEEE 802.3 collision detection system to abort transmission of the data packet. A subsequent series of phantom packets (that are invalid) provide carrier activity that inhibits retransmission of the packet. When the destination port is available, the phantom packets are stopped, permitting standard retransmission of the data packet. The switch includes prioritization mechanisms (e.g., a throttle count) to use when awarding priority to a port having backpressure applied.
Abstract:
A computer system is provided which includes a bus bridge coupled between a CPU local bus and a PCI bus. The bridge further includes a memory controller for controlling data transfers between a main memory and masters residing on either the CPU local bus or the PCI bus. A variety of peripheral devices are coupled to the PCI bus, including both real time resources and non-real time resources. For example, in one configuration, an SCSI controller, a network interface card, a video adapter, a video capture card, an audio adapter, and a telephony adapter are coupled to the PCI bus. A bus arbiter is advantageously provided for controlling and prioritizing ownership of the PCI bus based in part upon a real time indicator signal asserted by a bus agent that requires a real time data transfer. Each real time device is associated with a unique real time indicator signal. A relatively high level of arbitration priority is given to a master when it asserts its associated real time indicator signal at the time of a bus request. Bus agents which do not assert an associated real time indicator signal at the time of a bus request will lose the arbitration until all real time requests have been serviced. As a result, the system may support numerous real time processing resources while maintaining proper overall operation.
Abstract:
An adjacency matrix is incorporated into a local area network in order to provide smoother and faster transitions between mobile devices and access points of adjacent or overlapping microcells. The adjacency matrix can be based on fuzzy logic and updated periodically. Factors used to create the matrix can include the ability to establish a communication link, signal strength measurements, roam times, time of day, day of week and other factors germane to the local area network topology and patterns of its usage. The mobile device thus effects the transition by attempting to communicate on the frequencies associated with hopping schemes of the access points which are most likely adjacent to the previous access point. As a result, the average transition time is greatly reduced.