NXP I2C registration

It's from the '80s, so no patents are in force. According to Wikipedia, "no license fees are required" to implement the protocol (strange, since the licenses *had* to have run out). It also mentions that NXP charges for address allocation (why would anyone pay for that?).

Maybe they patented all the low integers?

John

Isn't Sesame Street prior art on numbers from 1 to 127 and the letters N, X, and P?

Presumably it's a nominal handling fee. Having a central authority control the address allocation ensures that random third-party devices don't have address collisions, although certainly a strictly local to the board use could get away with any address.

Sadly, there doesn't seem to be any current information at NXP, as the OP has noted. The links at

and

which each dead-end at a 404 Page Not Found.

The I2C manual (AN10216-01, from 2003) still notes "It is Philips's position that all chips that can talk to the I2C bus must be licensed. It does not matter how this interface is implemented. The licensed manufacturer may use its own know how, purchased IP cores, or whatever. This also applies to FPGAs. However, since the FPGAs are programmed by the user, the user is considered a company that builds an I2C-IC and would need to obtain the license from Philips."

Get real. With an address space of only seven bits, there *are* going to be collisions. How the hell does NXP know what devices (and how many) of each you're going to use? I see no purpose in "registration".

Yes, as you point out, they have supplied no mechanism for this. Seems XNP has milked this beyond their ability. ...and know it.

On Friday, December 30, 2011 9:13:16 AM UTC-7, snipped-for-privacy@att.bizzzzzzzzzzzz wrot= e:

be

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I2C is no longer used solely for its original purpose of intra-board, chip-= to-chip communications, and a good example of a use that doesn't fit into t= hat category and in which standardization of address assignment is very imp= ortant is in the VESA Display Data Channel standard, which is the de-facto = standard HW communications path for a number of popular video interfaces. = Every VGA- and DVI-equipped PC monitor or graphics card shipped for quite s= ome time uses the DDC interface, as does the popular digital-TV HDMI connec= tion. Without having standardization of the addresses at which various DDC = and other devices live within these sorts of systems, getting various produ= cts to talk to each other would be a nightmare. As it is, DDC-compatible c= omponents (such as EEROMs) can be made "prewired" to respond to the correct= addresses.

THAT'S why we still have "registration" in I2C-land. It clearly isn't all = that important when you're just using I2C as a means of connecting chips wi= thin a wholly-custom design on a single PCB, but that is far from all there= is to the subject.

Bob M.

chip-to-chip communications, and a good example of a use that doesn't fit into that category and in which standardization of address assignment is very important is in the VESA Display Data Channel standard, which is the de-facto standard HW communications path for a number of popular video interfaces. Every VGA- and DVI-equipped PC monitor or graphics card shipped for quite some time uses the DDC interface, as does the popular digital-TV HDMI connection. Without having standardization of the addresses at which various DDC and other devices live within these sorts of systems, getting various products to talk to each other would be a nightmare. As it is, DDC-compatible components (such as EEROMs) can be made "prewired" to respond to the correct addresses.

...and then it's *NOT* I2C.

important when you're just using I2C as a means of connecting chips within a wholly-custom design on a single PCB, but that is far from all there is to the subject.

Nonsense. ...and fix your line length.

On Friday, December 30, 2011 11:07:24 PM UTC-7, snipped-for-privacy@att.bizzzzzzzzzzzz >= =20

Ah, but it IS. And the example I gave remains a perfect example of why add= ress registration is still required. And I'm speaking as someone who was d= irectly involved in the development of the DDC and other similar standards = (such as the old ACCESS.bus spec).

Get a real newsreader.

Bob M.

LOL!

That's hilarious, coming from Google Groups ...

registration is still required. And I'm speaking as someone who was directly involved in the development of the DDC and other similar standards (such as the old ACCESS.bus spec).

You gave no reason at all. As usual, you're full of shit.

Too funny, groupie.

experience in the area of I2C and interface standards in general is what, exactly?

A *LOT* longer than you, moron.

nothing at all to do with the fact the someone complaining about "line length" must not have a particularly good reader (or else has one but doesn't know how to use it) themselves.

They were until you showed up. ...as usual.

xperience in the area of I2C and interface standards in general is what, ex= actly?

Yes, of *course* you have.

Look, you asked a question in a public newsgroup, the answer to which was q= uite obvious to any with actual experience in the field. Then you get your = Underoos all in a bunch because someone actually had the audacity to post t= hat answer. And now you continue to display the same high level of maturit= y and civil discourse as you've shown up to this point. Not exactly surpris= ing that someone might question how long you've actually been playing in th= is particular sandbox, is it? (And your complete ignorance of the second q= uestion in the above is, of course, noted.)

Bob M.