Abstract: A pre-stored vector interrupt handling system for rapidly processing interrupt requests from input/output (I/O) devices in processor-based systems includes selection logic and an interrupt vector store to quickly deliver a branch instruction from the interrupt vector store directly to the execution unit of a processor. The interrupt vector store is either pre-loaded with a table of the processor's branch instructions during system initialization or implemented in ROM. During normal operation, when an interrupt is received, a master interrupt signal is issued to the processor, which asserts an instruction cycle mode signal to external chip select logic. The chip select logic de-selects the program store and selects the interrupt vector store. An interrupt vector from the vector store is loaded onto the data bus and then directly into the execution unit of the processor.

Abstract: A content addressable memory system has rows and columns of CAM cells. Each CAM cell has a data memory, and comparison circuitry for comparing the data bit of the memory element with a compare data, and for driving a signal onto a match line when the data bit is not equal to the compare data. The comparison circuitry has a mismatch node with a pre-discharge device, and drives a match line drive device coupled to the match line. The mismatch node also couples to a first comparison device having source an output of the data memory and gate coupled to the compare data, and a second comparison device having source a second output of the data memory and gate coupled to compare data. Disclosed is a ternary implementation of the CAM cell also having a mask bit. Also disclosed is CAM timing such that the CAM cells operate without crowbar current.

Abstract: A content addressable memory system has an array of CAM cells. Each row of the array has a match line coupled to a match line pull device. The match line pull devices of each cell are also coupled to a row return line that may be shared with an adjacent row. Each row return line is coupled through a resistive device to a rail. The CAM cells also have a data memory element and comparison logic for comparing query data against the data memory element and controlling the match line pull devices.

Abstract: A CAM cell design methodology and a method of pre-charge and comparison timing is disclosed. A CAM cell utilizing this design methodology includes grounding circuitry and a P-channel transistor configured to communicate a comparison result to a match line using the Miller effect. In one embodiment, the CAM cell further includes a positive comparison bit line, a negative comparison bit line, a first dual-ended CAM memory core cell configured to store data, a second dual-ended CAM memory core cell configured to store masking data, comparison circuitry, and a second P-channel transistor configured to communicate a masked state to the match line.