(i.e. my company cannot deny that was I who wrote this and that), he can only give (exclusive) rights for somebody (e.g. a company) to use it.

That's semantics. What difference does it make if I "give my company exclusive rights" or "the company owns it" except to a lawyer who would charge $1000 for telling you the differences and concluding it is the same.

PS. You said your employees don't '51 profesionally, so you won't fire them if they would publish '51-related HW/SW here (unrelated to their job, of course), would you?
just to clarify: they are my companys employees, not "mine" and I do not own the company.
1) no
2) they would not know a '51 if they saw one
3) I keep preaching "you do this for 8 hours a day, do something else, like love your wife, in your free time"
4) if I were not doing electronics as my job, it would be very likely that would be my hobby

Erik