If you’re in need of a .NET managed client library for the K8090 board that can be used in 64-bit .NET projects (and on Linux / MacOS too, though that’s as yet untested), I have put together a new package that doesn’t use the Velleman C++ library and so can be compiled as x64.
Nuget package is here: NuGet Gallery | K8090.ManagedClient 1.0.0
Github project is here if you need the source: https://github.com/neilhewitt/K8090-Managed-Client
It’s a pretty thin layer over the K8090 serial protocol, so it should relatively self-explanatory, and there’s some docs at the Github project. Happy to accept PRs if you find and fix bugs, or else open a Github issue.
Note: This library is compiled for .NET 5.0 and above only. I am looking at dropping the requirement to the earliest version of .NET Standard that I can manage without having to bend the code too much, and if so I’ll update the Nuget package dependencies.