The XC2064 had programmable gates and programmable interconnects between gates, the beginnings of a new technology and market. Xilinx co-founders Ross Freeman and Bernard Vonderschmitt invented the first commercially viable field-programmable gate array in 1985 – the XC2064. Īltera was founded in 1983 and delivered the industry's first reprogrammable logic device in 1984 – the EP300 – which featured a quartz window in the package that allowed users to shine an ultra-violet lamp on the die to erase the EPROM cells that held the device configuration. However, programmable logic was hard-wired between logic gates. PROMs and PLDs both had the option of being programmed in batches in a factory or in the field (field-programmable).

The FPGA industry sprouted from programmable read-only memory (PROM) and programmable logic devices (PLDs). Many FPGAs can be reprogrammed to implement different logic functions, allowing flexible reconfigurable computing as performed in computer software.įPGAs have a remarkable role in embedded system development due to their capability to start system software (SW) development simultaneously with hardware (HW),Įnable system performance simulations at a very early phase of the development, and allow various system partitioning (SW and HW) trials and iterations before final freezing of the system architecture. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory. Logic blocks can be configured to perform complex combinational functions, or act as simple logic gates like AND and XOR. Circuit diagrams were previously used to specify the configuration, but this is increasingly rare due to the advent of electronic design automation tools.įPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects allowing blocks to be wired together. The FPGA configuration is generally specified using a hardware description language (HDL), similar to that used for an application-specific integrated circuit (ASIC). It seems that the timescale define at the file top is not read by the simulator.A field-programmable gate array ( FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturing – hence the term field-programmable. create the 1Hz signal when not in reset

$display('period is %f, high time is %f, and low time is %f',time3-time1,time3-time2,time2-time1) Signal clk_out has a period of 1 second and both high time and low time are 500ms. I have a signal (clk_out) from which I want to measure and auto-check the period and both high and low time. I have an issue while simulating my system with a verilog bench.

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