Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [fpga]

A Field-Programmable Gate Array (FPGA) is a logic chip consisting of an array of programmable logic blocks and interconnects that is configured by the customer after manufacturing—hence "field-programmable".

The FPGA configuration is generally specified using a hardware description language (HDL), mostly Verilog or VHDL.

References

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What is an LUT in FPGA?

I have gone through various sources... But I am not quite sure what it is.I want an and gate and the logical equivalent is two inputs feeding to one gate and for Y=AB' the logical equivalent is feeding to one not gate and one and gate. But it is the…
Muthu Subramanian
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What is an FPGA?

I've seen a lot of people talking about FPGA's before and I know that it stands for field-programmable gate array but how does it work and what is the purpose of using an FPGA?
zklapow
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Why are FPGAs so expensive?

I mean compared to ICs (ASICs) with similar complexity, speed etc. Let's compare Ethernet switches to Kintex FPGAs (note that the most expensive switch from the list is circa as expensive as the cheapest Kintex): FPGAs are well structured ICs (like…
betontalpfa
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Can you actually break an FPGA by programming it wrong?

Can you actually break an FPGA by programming it incorrectly? I'm a software guy really. It's no secret that if your software is wrong, you could destroy all sorts of important data, and perhaps even crash the whole machine. But it's really…
MathematicalOrchid
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Can FPGAs dynamically modify their logic?

It would be theoretically possible for an FPGA to write a configuration image to an external memory, and load the configuration image from the memory to reconfigure itself. This would be "non-dynamic" reconfiguration. Do FPGAs have the ability to…
Randomblue
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Why are the lookup tables in FPGAs small?

An FPGA can be seen (visually at least) as a matrix of cells. Each cell has a LUT (look-up table) inside, implemented with SRAM and MUX. Why does the size of such a LUT (and hence of the SRAM) need to be kept small in FPGAs (usually less than 10…
Hadi El Yakhni
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Export restrictions on components like FPGAs

I'm considering upgrading the FPGAs on a product of mine from small Spartan3A-200s to low-to-mid-scale Spartan6s. The Spartan6s are actually cheaper, and I've just about outgrown the 200. It looks like it'd be a mistake to design in another…
darron
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Why are multipliers 18x18 Bit in FPGAs?

I'm looking at different FPGAs for my dissertation project and I keep seeing that the multiplier blocks are 18x18 bit, why is this? Why are they not 16-bit?
Dean
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How to measure phase difference of two signals of the same frequency in an FPGA?

How to measure phase difference of two signals of the same frequency in an FPGA? For instance, say I have two 150 MHz signals (internal to the FPGA) that are synchronous to each other, but they are offset by some constant phase difference, how would…
cksa361
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How to perform small value approximation for sqrt(x) on FPGA

I am trying to implement a fixed point routine which involves computing the value of \$ \sqrt{x} \$ for small \$x\$ that approaches \$0\$. The target architecture is an FPGA. One problem is that this function does not lend itself easily towards the…
Ang Zhi Ping
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how to properly save an architecture in a fpga ic forever

Considering I made an architecture to do some specific thing, wrote in vhdl, for example. Can I 'burn' it in a fpga chip, forever? Or how should I do it, protecting the intelectual property knowing the fact it can be read from the serial flash…
Ratata Tata
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Are FPGA's as powerful as the number of gates they have?

Let's say I have a 1 million gate FPGA. I've found a few processors on OpenCores which only require 50k gates. So would it be possible to make, say, an 8 core processor with such an FPGA? Or are there limits to FPGAs when it comes to implementing…
Thomas O
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Cheap/old consumer devices to recover FPGA boards from

Various FPGA suppliers claim that their devices are increasingly used in mass-market consumer devices. Given the general depreciation of device prices with time, and high price for even old FPGA boards, this opens possibility to "scavenge" the…
silvio
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How much current does an FPGA consume, anyway?

I'm in the R&D stages of a V4 of my project, which may replace the high-speed DSP with an FPGA. I was looking at this FPGA, because it is cheap: XC3S50A (about £6.50/each.) I think I can probably fit the project onto there, with one concern. I can't…
Thomas O
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How to calculate the required number of FPGA logic elements?

I have a Lynxmotion hexapod which uses hobby servos for each of its 18 degrees of freedom (DOF). The basic problem with this is that I cannot get data on the joint angles. I have modified the servos so that I can measure their orientation via the…
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