Does the codes are different for various brands of FPGA?

Hi guys,

I am new to FPGAs. I am a microcontroller hobbiest. I have few questions regarding FPGAs:

1) If I program logic in VHDL or Verilog like all digital systems the code will ultimately be binery. In micocontrollers we user assembler or compilers and ultimately generate hex or bin file which is different for different brands (e.g. 8051 & 68HC11). Does code (binery, I mean the lowest level code in FPGA) generated for FPGA works for all brands of FPGA or the code is different for different brand of FPGA? Can I use same binery code file (whatever in the case of FPGA I don't know as yet, please tell me) in different brand of FPGA? That is does all brand (xilinx, atmel etc.) accept the same code or it is different like microcontroller.

I am asking it because I know FPGAs are composed of thousands(even millions) of gates and flip-flops. My question is in an SRAM or FLASH or EPROM we can store programs and it is same for different brands because it has a standard Address bus and data bus.

I don't know have I made myself clear or not.

2) If I can replace between brands, what would be the criterias to look at? e.g. in case of SRAM I can replace it with same or larger capacity SRAMs of different brand (timing and and control is understood). Should an FPGA with same gate no and same I/O pin count of different brand be used using the same (lowest level)code?

FPGA learner

First of all, VHDL & Verilog are hardware description languages used either for creating simulation models or synthesizing a digital system. Lets concentrate on the second usage which is about your question. To design a digital system you should write what is called RTL (Register Transfer Level) in which you describes both combinational and sequential parts of your design (not a binary code , it is a description code).
About code portability, of course it is not like microcontrollers , as in microcontrollers you are writing some code for a dedicated hardware, here you are building your hardware. No matter which FPGA you are going to implement your code on it, the same code can be implemented anywhere (it is all about FFs and logic gates)

FPGA learner

So its portable in RTL. But what about the lowest level? The file which is stored in the FLASH and downloaded into the FPGA at startup, what is it called.

Does this file accepted by all brands of FPGAs?

FPGA learner

If you are asking about the .bit file, so it is not portable as it is technology dependent, but if you have the RTL description of this digital system then you can generate the .bit file for any FPGA.

FPGA learner

Does the FPGA manugacturer or other vendor have converters which can convert the .bit to RTL? So that I can go for a different brand.

FPGA learner

Most probably no, but i am not sure

Re: FPGA learner

the bit file depends on how the tool synthesizes the RTL code you wrote
for the bitstream to netlist conversion it's possible, for FPGA to ASIC conversion for instance; but i don't have details more
you can see this, it gave me a hint that this can happen

**broken link removed**