Abstract:
A method and apparatus for comparing a stored data word to a comparison data word in a magnitude content addressable memory (MCAM) are disclosed. Each cell of the MCAM includes a data memory cell for storing a data value and a magnitude comparator, coupled to the first memory cell. The magnitude comparator receives the data value and a comparison value as inputs, and produces two magnitude signals as outputs. The first magnitude signal indicates whether the comparison value is greater than the data value and the second magnitude signal indicates whether the comparison value is less than the data value. The magnitude comparator also receives magnitude signals from the preceding MCAM cell. The previous magnitude signals are output as the first and second magnitude signals when the data value and the comparison value are equal. The MCAM enables data words of arbitrary length to be compared with comparison words. The MCAM cell may contain a second memory for storing a mask value. When the mask value is set, the MCAM cell operates as if the comparison and data values were equal.
Abstract:
A priority encoder can be used for a Content-Addressable Memory (CAM) device that typically has an array of CAM cells arranged in columns and rows with each row having a match signal indicative that compare data has matched data within the respective row. A priority encoder is operatively connected to the array of CAM cells and determines a highest priority matching address for data within the array of CAM cells. The priority encoder includes match lines associated with respective rows and precharged bus lines connected into respective match lines that are discharged whenever there is a match signal such that the highest precharged bus line discharged results in an encoded address.
Abstract:
A programmable priority encoder is disclosed for use with the device such as a Content Addressable Memory (CAM) device having a plurality of array objects to be encoded in binary and arranged in row and columns. Match lines are adapted to be connected to a plurality of arrayed objects associated with respective rows. A plurality of encoder cells, each having a memory element and forming an encoder block are arranged in rows. Precharged bus lines are operative with the encoder cells and match lines. The precharged bus lines are discharged indicating a match and priority is assigned to rows based on logic values stored within the memory elements of the encoder cell.
Abstract:
A Content Addressable Memory (CAM) circuit includes memory cells preferably formed as two memory cells each having internal nodes. A compare circuit is operative with the memory cells. A common terminal (VPL) exists for the memory cells. Capacitors are added between the internal nodes of each of the memory cells and common terminal for memory cell stability.
Abstract:
A priority encoder can be used for a Content-Addressable Memory (CAM) device that typically has an array of CAM cells arranged in columns and rows with each row having a match signal indicative that compare data has matched data within the respective row. A priority encoder is operatively connected to the array of CAM cells and determines a highest priority matching address for data within the array of CAM cells. The priority encoder includes match lines associated with respective rows and precharged bus lines connected into respective match lines that are discharged whenever there is a match signal such that the highest precharged bus line discharged results in an encoded address.
Abstract:
A programmable priority encoder is disclosed for use with the device such as a Content Addressable Memory (CAM) device having a plurality of array objects to be encoded in binary and arranged in row and columns. Match lines are adapted to be connected to a plurality of arrayed objects associated with respective rows. A plurality of encoder cells, each having a memory element and forming an encoder block are arranged in rows. Precharged bus lines are operative with the encoder cells and match lines. The precharged bus lines are discharged indicating a match and priority is assigned to rows based on logic values stored within the memory elements of the encoder cell.
Abstract:
A priority encoder can be used for a Content-Addressable Memory (CAM) device that typically has an array of CAM cells arranged in columns and rows with each row having a match signal indicative that compare data has matched data within the respective row. A priority encoder is operatively connected to the array of CAM cells and determines a highest priority matching address for data within the array of CAM cells. The priority encoder includes match lines associated with respective rows and precharged bus lines connected into respective match lines that are discharged whenever there is a match signal such that the highest precharged bus line discharged results in an encoded address.
Abstract:
A Content Addressable Memory (CAM) circuit includes memory cells preferably formed as two memory cells each having internal nodes. A compare circuit is operative with the memory cells. A common terminal (VPL) exists for the memory cells. Capacitors are added between the internal nodes of each of the memory cells and common terminal for memory cell stability.