GPL3.0

[the-moog]

Is this source code deiberately GPL3.0?

Only that means that, as it stands, this project can only be used in GPL3.0 compatible 'copy left' hardware as the act of synthisising it and loading into an FPGA is akin to a static link.
Giving both project owners and contributors equal access and rights to both sets of IP. That makes using this in any commercial product almost impossible, even if not for profit, e.g. internal test equipment.
Would you consider adopting a similar but less restrictive license, e.g. Apache or MIT? Or perhaps dual licence?

[lnchan]

If you'd look at issue #13, copyleft seems to be a deliberate choice, yes.

[the-moog]

@lnchan I took a look at #13 and added (a rather verbose, for which I apologise. I do ramble sometimes....) comment as an explanation to yourself and others why GPL3 can't work in most FPGA projects.

[mangelajo]

Yes, GPL3 is a very hard license, it means that you need to share not only your library when used, but also any code that you compile together with your library.

I'd recommend something lighter light the MIT license, (i.e. https://github.com/SpinalHDL/VexRiscv/blob/master/LICENSE ) , Apache license, or similar.

But anyway, I would like to use the lines here to congratulate you for the impressive work you have done here @WangXuan95

Thank you for sharing with us all!.

[mangelajo]

Also look at LGPL, this would help wider adoption of your library, while still ensuring that people will contribute back fixes and code to FPGA-USB-Device.