why not just say I2C?

Question

I am currently working with a range of peripherals whos control lines look remarkably like an I2C interface.

The data sheets go into great detail about how the data and clock line are used to communicate with the device and how it has an own 'address' so that you can differentiate it from other devices etc.......

Why not just say that it's an I2C comptable device FFS.

Do they have to pay Philips some extra money for admitting that it's I2C rather than pretending that it is something else?

(and is it really still in patent after 20 years?)

sorry rant over.

tim

peterk · Accepted Answer

Just call it SPI like everybody else. It's probably more of a trademarkthan a patent issue in the same way you can't call your latest vacuumcleaner a Hoover.Peter

Grant Edwards · Answer

Because I2C and SPI aren't very similar at all?

-- Grant Edwards grante Yow! I'LL get it!! It's at probably a FEW of my visi.com ITALIAN GIRL-FRIENDS!!

larwe · Answer

SPI is not I2C. SPI is to "three-wire interface" as I2C is to "two wire interface". Or to put it another way, SPI is to Motorola as I2C is to Philips.

Also, note that "I2C-like" peripherals are in no way guaranteed to be FULLY I2C compatible.

Spehro Pefhany · Answer

I think you mean "two wire". Best regards, Spehro Pefhany-- "it's the network..."                          "The Journey is the reward"             Info for manufacturers:  software/hardware/analog  Info for designers:

peterk · Answer

Oops, of course you are right, it's TWI. I should put my brain intogear before writing.Peter

Gene S. Berkowitz · Answer

Well, yes, they DO have to pay Philips if they use the term "I2C" or "IIC".In exchange, Philips grants them a unique device identifier for their product.It's also a trademark.--Gene

Mike Harrison · Answer

Not always - only if it is a new type of device - e.g. all eeproms have the sameaddress prefix.

surftom · Answer

Last I heard, I2C was a registered trademark and you had to pay Philips for using it. There's a lot of these shenanegans being played - OneWire, SPI, I2C etc. I think that manufacturers have tried to play by the rules and still let you know what they mean - Atmel uses the TWI - Two wire interface that can be used with I2C

But you're right - it is annoying

Tom

tim wrote:

Ulf Samuelsson · Answer

skrev i meddelandetnews:Yes, you should ask Philips to adopt the TWIso we can have one standard :-)-- Best Regards,Ulf Samuelsson   This is a personal view which may or may not beshare by my Employer Atmel Nordic AB

tim · Answer

stupid me for posting the day before I went on my Xmas leave but...

Ah ha, so the name is trademarked and you have to pay Philips to use it, but the invention is (probably) out of patent so you are free to use it in a design if you don't say so.

Ta

tim

why not just say I2C?

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