Fpga lut to asic gates verification#
Fpga lut to asic gates series#
Fpga lut to asic gates free#

Similarly with flip flops, muxes and so much other devices. Thus I bet that the digital design of logic elements is more extensive (consider also FET's which may have different configurations). Some simple rule such as 'when the number of bits is < then.', 'when the depth is <, then.' etc.īuilding half gates from a NAND gate considering its transistor count is not always correct, from the next picture you can see that there is only one transistor and four diodes. In my designs I often consider small memories such as 64x8 or 128x16 and I'd really like to understand when one method is better than another. I assume that there's some overhead here. From the above, RAM cells seem so much better but I remember a friend of mine telling me years ago, for a 256x8 RAM that 'it wasn't worth it, might as well doing it with FFs'. RAMs cell = 6T/bit = 1.5 gates/bit, dual port = 8T = 2 gates/bit

RAMs made with D FFs => 7-10 gates/bit + suitable muxes (see above). How do I extend this to multiple input muxes ? What's the trade off with gate muxes ?įrom this discussion, muxes tend to be transmission gate.Įnabled, synchronous D FF = D FF + MUX2_1 = 6 + 4 = 10 gates, 6 + 1 (transmission gate mux) = 7 gates, 6 + gated clock = 7 gates ? Which one is more common ? Mux 2:1 with transmission gates = 4 T = 1 gate If anyone has some more data points for MUX 4:1, 8:1, 16:1, etc Multiple input muxes can be built from MUX2_1 or with multiple input NANDs (see above) MUX 2 :1 = 4 gates or 3 NAND2 + NOT = 3.5 gates ? N inputs NAND = 2*N T = N/2 gates ? Max reasonable N ? Two input AND = NAND2 + NOT = 1.5 gates ? Two input NAND (NAND2) = 4 T(ransistors) = 1 gate

Fpga lut to asic gates free#

Please feel free to correct, comment, expand.

Fpga lut to asic gates series#

If you’re interested in learning how the Open Source FPGA tool flow works from end to end, check this video series I did for Symbiotic EDA.I'd like to be able to estimate gate counts of different designs for the purpose of architectural exploration.īelow is what I found out. If you want to buy an FPGA board to play with and help you learn digital design, I recommend going for one with an active, supportive community: But with an FPGA I can actually plug it into a real screen and see it works. For example I can simulate my vga clock, and even simulate the screen. The lookup table can be programmed to model any type of gate - for example an inverter or a 4 input NAND.Īn FPGA board can help you test your digital design at speed. These usually contain a lookup table, a flip-flop and some carry-logic (speeds up addition).

These pictures are of the Lattice iCE40 FPGA. Additionally you need a tool that can take the finished bitstream and send that to the FPGA for programming.Īn FPGA consists of a huge amount of repeated logic elements/blocks/slices.

Fpga lut to asic gates verification#

FPGAs need synthesis, place and route, simulation and verification tools. They have a reasonable overlap of the tools required to design for them. Could include multipliers, memory controllers or other high speed interfaces.

Have a very limited set of standard cells - at the least lookup tables, flip-flops, memories.

Can program your digital design onto them, over and over again.

Available to buy blank chips cheaply, off-the-shelf.

If millions of devices need to be made, then an ASIC is probably going to be much cheaper than using FPGAs for the same function, and will have higher performance.Īn FPGA is quite like an ASIC, but has some major differences. This allows the designer to get a result more quickly, which can be useful for prototyping, and is much cheaper if only a small number of the chips need to be produced. An FPGA, or field programmable gate array, is a way to implement a digital circuit on a chip without fabricating it from scratch.