Abstract: A CAM cell array according to embodiments of the present invention include an array of CAM cells, each of the CAM cells comprising a first cell, the first cell including a non-volatile storage element coupled to at least one first data line and a match line; a match line controller coupled to the match line; and a data line controller coupled to the data lines, wherein a write operation is performed by changing a state of the non-volatile storage element by providing data to the at least one data line, wherein a read operation is performed by determining the state of the non-volatile storage element through the at least one data line, and wherein a comparison operation is performed by applying data to the at least one data line and determining a match condition on the match line.

Abstract: A content addressable memory (CAM) system that includes a row of NAND-type CAM cells divided into a plurality of segments. Each segment includes a plurality of series-connected switching transistors, wherein each of the switching transistors is part of a corresponding NAND-type CAM cell. The series-connected switching transistors of each segment are coupled to the series-connected switching transistors in an adjacent segment by a repeater circuit, thereby forming a chain of series-connected switching transistors and repeater circuits. A match line driver circuit is coupled to one end of the chain, and a match line is connected to the other end of the chain. If a match condition exists for the entire row, then a signal driven by the match line driver is propagated to the match line, through the chain of series-connected switching transistors and repeater circuits.

Abstract: A DMA interrupt coalescer processes interrupts received from a DMA channel of a DMA controller by transmitting an interrupt request to an interrupt controller if a coalescing condition is satisfied after receiving one or more delayable interrupts, or transmitting the interrupt request regardless of the satisfaction of the coalescing condition if a non-delayable interrupt is received. The coalescing condition is satisfied if a non-zero period of time has transpired since a first of the one or more delayable interrupts was received, or if a number of the one or more delayable interrupts received exceeds a programmed value.

Abstract: A process and system for estimating the occurrence of single event latch-up in an integrated circuit. The process involves determining the resistance between each junction and the closest appropriate tap in a regular shaped well. Each junction occurring in an irregular-shaped well is also identified. Finally, the method may make suggestions for lowering the probability that single event latch-up may occur in the integrated circuit.

Abstract: A method and apparatus for testing semiconductor wafers is disclosed in which a test circuit is used that includes a waveform generator. The test circuit can test a single transistor or can test multiple transistors. A testing method is disclosed in which a supply voltage is applied to the waveform generator to produce pulses that are applied to the gate of a transistor to be tested. A bias voltage is applied to the source and drain of the transistor to be tested, and the charge pumping current that is generated at the substrate is then measured. The process can be repeated at different bias voltage levels to obtain additional current measurements, indicating the maximum charge pumping current for the transistor that is being tested. The determined maximum charge pumping current can then be used for determining whether there is excessive 1/f noise in the device under test.

Abstract: A content addressable memory array includes a plurality of rows of active CAM cells electrically coupled to a corresponding plurality of active match lines and at least one row of dummy cells, which are configured to generate an always-match condition on a dummy match line when the CAM array is undergoing a search operation. A match line pull-up circuit is provided. This match line pull-up circuit is electrically coupled to the plurality of active match lines and the dummy match line. The pull-up circuit is responsive to a calibration control signal that sets a pull-up strength of the match line pull-up circuit when the CAM array is undergoing the search operation. A sense amplifier, which is coupled to the match lines, includes a control circuit configured to adjust the calibration control signal in response to evaluating a first voltage on the dummy match line relative to a reference voltage.

Abstract: A base address matching device and method are disclosed. In a switching device having a plurality of input/output ports, a routing device has been described that has an array of registers in which each register holds content associating an address with one of the input/output ports in the switching device and elements of the content in the array of registers are pre-sorted into a specified order, and an address matching element that has a plurality of comparators that are electrically coupled to selected registers in the array of registers. The base address matching element is able to select a matching address from the content of the array of registers and to direct a communication packet to one of the ports in the switch by matching the target address in the packet to an address in the content of the register in the array of registers associated with the port.

Abstract: Multi-queue first-in first-out (FIFO) memory devices include multi-port register files that provide write count and read count flow-through when the write and read queues are equivalent. According to some of these embodiments, a multi-queue FIFO memory device includes a write flag counter register file that is configured to support flow-through of write counter updates to at least one read port of the write flag counter register file. This flow-through occurs when an active write queue and an active read queue within the FIFO memory device are the same. A read flag counter register file is also provided, which supports flow-through of read counter updates to at least one read port of the read flag counter register file when the active write queue and the active read queue are the same.

Abstract: Capacitive coupling correction circuits are coupled between adjacent parallel dynamic (pre-charged) or static conductors. The capacitive coupling correction circuits effectively isolate a low voltage applied to a first conductor from a high pre-charged voltage stored on an adjacent second conductor (or vice versa). The adjacent parallel conductors can be bit lines of a memory cell. Each capacitive coupling correction circuit can include an inverter having an input terminal coupled to the first conductor, and an output terminal coupled to a first plate of a capacitor. A second plate of the capacitor is coupled to the second conductor. The capacitance of the capacitor is selected to be identical to a parasitic capacitance between the first and second conductors. As a result, there is a zero net voltage effect between the first and second conductors. The capacitive coupling correction circuits may be distributed along the length of the first and second conductors.

Abstract: The methods and systems presented herein provide an improved means of correcting the variation of Voltage Output Differential (VOD) in differential drivers. In some embodiments, a high-precision reference voltage is generated not only based on a desired VOD, but also by monitoring the Voltage Common Mode (VCM) in a differential driver. In some embodiments, the VOD is then compared with the high-precision reference voltage to correct the output current. The result is a low-variation output voltage.

Abstract: A ring oscillator circuit having an odd plurality of inverter stages (i.e., 2N+1 stages). In accordance with one embodiment of the present invention, only one of the inverter stages is operated in response to a variable input voltage, while the remaining inverter stages are operated in response to a highly filtered constant input voltage. The inverter stages that operate in response to the constant input voltage oscillate at a base frequency. The inverter stage that operates in response to the variable input voltage causes the frequency of the output signal to deviate from the base frequency by an amount determined by the variable input voltage. In this manner, the variable voltage inverter stage implements frequency control for the ring oscillator. The gain of the ring oscillator circuit is reduced by a factor of (2N+1) with respect to the gain of a conventional ring oscillator.

Abstract: A content matching engine (CME) uses a content addressable memory (CAM) array that stores a plurality of strings in separate entries. The strings define one or more rules to be matched. The strings of each rule are linked, thereby providing a required order. The strings of each rule can be linked by per-entry counters associated with each string, or by a state machine. The strings in the CAM array are compared with a packet, which is shifted one symbol at a time (because the strings can start on any boundary). When the CAM detects a match, the CAM skips over the string that resulted in the match, thereby preventing erroneous matches. The CAM allows parallel matching to be performed for multiple rules. If the contents of a packet match all of the strings of a rule, in order, then the CME asserts a match/index signal that identifies the matched rule.

Abstract: A photomask and a method for forming a photomask are disclosed in which the photomask pattern is modified to bridge features that are likely to produce electrostatic discharge related defects. In one embodiment those adjacent features that are closely spaced together and have a high surface area differential, are bridged using a bridge that has a width less than the minimum optical resolution of the photolithography process.

Abstract: A serial buffer is provided having a parallel port configured to couple the serial buffer to a first system via a parallel interface protocol. The serial buffer also includes a serial port configured to couple the serial buffer to a second system via a serial interface protocol and control logic that enables data to be transferred between the parallel port and the serial port in an efficient manner. In one embodiment, the parallel interface protocol is substantially identical to a quad-data rate burst of two (QDRII-B2) interface protocol.

Abstract: On-chip resources of a serial buffer are accessed using priority packets of a Lite-weight protocol. A priority packet path is provided on the serial buffer to support priority packets. Normal data packets are processed on a normal data packet path, which operates in parallel with the priority packet path. The system resources of the serial buffer can be accessed in response to the priority packets, without blocking the flow of normal data packets. Thus, normal data packets may flow through the serial buffer with the maximum bandwidth supported by the serial interface. The Lite-weight protocol also supports read accesses to queues of the serial buffer (which reside on the normal data packet path). The Lite-weight protocol also supports doorbell commands for status/error reporting.

Abstract: A serial buffer includes queues configured to store data packets received from a host. A direct memory access (DMA) engine receives data packets from the highest priority queue having a water level that reaches a corresponding watermark. The DMA engine is configured in response to a DMA register set, which is selected from a plurality of DMA register sets. The DMA register set used to configure the DMA engine can be selected in response to information in the header of the read data packet, or in response to the queue from which the data packet is read. Each DMA register set defines a corresponding buffer in system memory, to which the data packet is transferred. Each DMA register set also defines whether the corresponding buffer is accessed in a wrap mode or a stop mode, and whether doorbell signals are generated in response to transfers to the last address in the corresponding buffer.

Abstract: A serial buffer having a parser and multiple parallel processing paths is provided. The parser receives incoming packets, determines the type of each packet, and then routes each packet to a processing path that corresponds with the determined packet type. Packet types may include blocking priority packets (which implement bus slave operations), non-blocking priority packets (which access on-chip resources of the serial buffer) and data packets (which implement bus master operations). Because the different packet types are processed on parallel processing paths, the processing of one packet type does not interfere with the processing of other packet types. As a result, blocking conditions within the serial buffer are minimized.

Abstract: Status/error reporting is implemented using a doorbell system. A plurality of flag registers are included on a system device, such as a serial buffer. Each flag register has a corresponding address, and stores a plurality of flags. A flag scan controller accesses the flag registers in a predetermined priority order, using the flag register addresses. Upon detecting that one or more of the flags of a flag register are activated, the flag scan controller causes a doorbell command to be generated. The doorbell command includes the flag register address and the corresponding flags. A system processor receives the doorbell command and services the activated flags. Once the activated flags are serviced, the system processor performs one or more software write operations to clear the flags within the system device. The system processor can simultaneously service multiple flags. The system processor can also simultaneously clear multiple flags.

Abstract: A charge recycling integrated circuit and a method for integrated circuit charge recycling. In one aspect, a charge storage collector is interposed between a high voltage supply or a low voltage supply and a function block of the integrated circuit. The charge collector is operable to selectively store a charge dissipated in the function block when the logic circuitry of the function block switches between a high voltage value and a low voltage value. The dissipated charge resulting from the switching in the logic circuitry of the function block is selectively stored to the charge collector and the charge collector selectively returns the charge stored on the charge collector to the high voltage supply, the low voltage supply or to another node in the integrated circuit as appropriate.

Abstract: A self-biased electrostatic discharge (ESD) protection circuit for protecting an integrated circuit operating in a normal voltage range that includes both positive and negative voltage levels is disclosed. The self-biased ESD protection circuit includes an input connection for receiving an input voltage, a protection transistor electrically coupled to the input connection, and an electrical sink. The protection transistor is operable to provide ESD protection from the input connection to the electrical sink. The self-biased ESD protection circuit also includes a metal oxide semiconductor (MOS) biasing network electrically coupled to the input connection and the protection transistor. The MOS biasing network is operable to cause the protection transistor to remain in a non-conductive state when the input voltage is in the normal operating voltage range.