Is the 8051 architecture public domain?

Lots of companies have 8051 compatible chips... Atmel, Dallas, Philips, Siemens...

Is the 8051 CPU public domain, which could explain why so many guys chose to use it? Or do these guys still have to pay royalties to Intel?

Thanks.

Reply to
Jean Nicolle
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They pay a license fee to the provider of the IP for the 8051. The provider pays a license to Intel.

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Reply to
Kevin D. Quitt

Sounds reasonable although Intel designed the 8051 in the 1980s, 25 years ago... Do you know if the 8051 will eventually become public domain (like their patents will expire or something like that). Jean

Reply to
Jean Nicolle

Well, there is an OpenCore for that (actually several):

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Which implies that people out there aren't being sued.

I don't believe your question is that simple. Companies have tried, I believe unsucessfully, to patent instruction sets. So if someone makes a microprocessor that happens to execute the same code, but was designed without copying the internal logic, that is not a problem. Busses are a bigger problem. One of the reasons AMD came out with different bus standards than Intel was to get around that.

Now Intel has sued people who cloned their instruction sets based on the very dubious idea that "they must have used our ideas to do that", but again, they have failed to make their case in court, and in one case, were given a stern lecture from the judge for attempting what amounted to a "blind legal attack" using that tactic.

Reply to
Scott Moore

Kevin D. Quitt writes about 8051 clone chips

Probably, unless they designed the IP themselves, which I expect most of them did. Though I don't have any hard facts.

Not bloody likely. Any patents on the 8051 have expired.

Reply to
Eric Smith

In that case, I take it all back.

-- _ Kevin D. Quitt snipped-for-privacy@Quitt.net 96.37% of all statistics are made up

Reply to
Kevin D. Quitt

No, because there isn't really such a thing as "the" 8051 CPU. There are dozens of apparently indepedent designs that all share a single machine language and core features (timers, UARTs, ...), but differ in various ways, starting from the number of clock cycles it takes for one machine cycle to execute being anywhere between the original 12 and 1, and extending to CPUs that changed even some aspects of the machine language.

No. Some of them may have done so in some time long gone, but not these days.

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Reply to
Hans-Bernhard Broeker

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