Before the advent of programmable logic, custom logic circuits used to be fabricated at the board level by employing standard components. Another alternative was gate level fabrication in application specific integrated circuits, which were very costly. Field Programmable Gate Array (FPGA) is an integrated digital circuit which comprises numerous identical logic cells. Every logic cell could perform an operation independently. All cells are interconnected by an array of programmable switches and wires. An application specific design could be implemented by defining a simple logic function for every cell and closing the programmable switches by selection. The matrix of interconnected logic cells constitutes the basic building block of logic circuits. Complicated designs could be implemented by combining these building blocks with the aid of a PC support provider.
Logic Cell – The Basic Building Block Of FPGA
The functionality of a logic cell varies widely from device to device. Usually each logic cell consists of few binary inputs and outputs as per the Boolean logic operation specified in the user application, logic gates and other digital circuits. The user could register the combinatorial output of the cell to implement the clocked logic. The same combinatorial logic could also be implemented as a Look Up Table memory (LUT) or a set of logic gates and multiplexers. A standard logic cell comprises 4 input LUT, a D type Flip Flop, a Full Adder (FA) and a multiplexer. The outputs of the LUT are directed to the FA and multiplexer. The logic block could operate in 2 operating modes, namely Normal Mode and Arithmetic Mode. The operating mode could be selected by programming the multiplexer with the help of a tech support provider.
A few logic cells constitute a logic block. The most basic FPGA architecture comprises a matrix of configurable logic blocks, I/O pads and routing paths. All routing paths usually have same width or number of wires. Numerous I/O pads could be put into the width of one column or the height of one row in the matrix. The application design should be mapped into the FPGA with sufficient resources. The required number of logic blocks and I/O pads should be specified by the detailed design. The number of routing tracks usually depends on the design complexity. The FPGA manufacturers provide sufficient routine tracks to implement any complicated design. The FPGA routing is usually unsegmented. A switch box is present at the intersection of horizontal and vertical routes. Before being terminated in the switch box, each wiring section traverses only one logic block. Longer routes could be formed by turning on the multiple programmable switches in the switch box. The complicated FPGA architecture could be easily understood with help of a PC support provider. More about newest FPGA software
FPGA Programming And Design
The designer uses some standard tools, such as Hardware Description Language (HDL) or Schematic Design, to specify the FPGA behavior. In the cases, where large-scale structures are involved, HDL is more suitable than Schematic Design, because it is easier to define each component numerically than drawing each component by hand. Visual presentation is an advantage of Schematic Design. If any problem occurs while using the HDL or Schematic Design, the user should consult an experienced tech support provider. For resolving interface problems between the computer and the programmer, the computer service providers, such as IBM support or providers should be consulted.