Atmel Corporation

Robert B Luking

Frederick Furtek

Martin T Mason

A field programmable gate array with a matrix of rows and columns of programmable logic cells interconnectable to each other by a network of local and express bus lines and to I/O pads at the perimeter of the logic cell matrix and bus network, is characterized by having a set of reset lines which include main reset lines, column reset lines, and sector reset lines. Each of the main reset lines receives a different reset signal. Each of the column reset lines is associated with a particular column of logic cells of the matrix. Each column reset line is selectively connectable to any one of the main reset lines to receive a selected reset signal. Each of the sector reset lines is connected to a subset of the logic cells in a column. The column reset lines are selective connectable to the logic cells in this respective associated columns by means of the sector reset lines that are connectable to the column reset lines.

FPGA structure having main, column and sector reset lines

A field programmable gate array with a matrix of rows and columns of programmable logic cells interconnectable to each other by a network of local and express bus lines and to I/O pads at the perimeter of the logic cell matrix and bus network, is characterized by having a set of clock lines which include main clock lines, column clock lines, and sector clock lines. Each of the main clock lines receives a different clock signal. Each of the column clock lines is associated with a particular column of logic cells of the matrix. Each column clock line is selectively connectable to any one of the main clock lines to receive a selected clock signal. Each of the sector clock lines is connected to a subset of the logic cells in a column. The column clock lines are selective connectable to the logic cells in this respective associated columns by means of the sector clock lines that are connectable to the column clock lines. A circuit for selectively inverting clock signals may be located along each sector clock line.

FPGA structure having main, column and sector clock lines

A field programmable gate array has a matrix of programmable logic cells and a bus network of local and express bus lines. The bus network effectively partitions the matrix into blocks of cells with each block having its own distinct set of local bus lines. Express bus lines extend across more than one block of cells by means of repeater switch units that also connect local bus lines to express bus lines. The grouping of cells into blocks with repeaters aligned in rows and columns at the borders between blocks creates spaces at the corners of blocks that can be filled with RAM blocks, other memory structures, specialized logic structures or other dedicated function elements that are connected to the bus network. The RAM blocks can be single or dual port SRAM addressed through the bus lines. Pairs of adjacent columns of RAM blocks may be commonly addressed by the same set of bus lines. Other specialized or dedicated logic might also fill those corner spaces. Logic cells are directly connected to neighboring cells, including diagonally adjacent cells, and are also connected to local bus lines. The arrangement of express bus lines is preferably staggered in such a way that they connect to non-consecutive repeaters in an alternating manner. I/O pads connect to cells at the perimeter of the matrix and to the bus network. Preferably, pads are connectable to more than one cell and more than one row or column of bus lines, and each perimeter cell can be connected to any of several I/O pads.

FPGA logic cell internal structure including pair of look-up tables

A field programmable gate array (FPGA) comprising a matrix of programmable logic cells, a bus network of local and express bus lines, and a system of perimeter I/O pads is disclosed. Logic cells are directly connected to neighboring nearest cells, including diagonally and orthogonally adjacent cells, and are also connected to local bus lines. Such direct cell-to-cell connections allow both directions of signal propagation. I/O pads connect to cells at the perimeter of the matrix and to the bus network. Preferably, I/O pads are connectable to more than one cell and more than one row or column of bus lines, and each perimeter cell can be connected to any of several I/O pads.

Growing community of inventors

Catonsville, MD, United States of America

Robert B Luking