Any guidelines in selecting I2C addresses?

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I'm wondering if there is a particular range of I2C addresses that are either reserved or recommended for end-user use. I know that <=7 and >=0x78 are not allowed, but I haven't found anything about either mandatory or suggested "band plans" for choosing addresses in the allowed range.

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If you are setting the addresses yourself, then just use whatever addresses you want. I believe that even the reserved addresses are for multi-master mode, so if you are not doing that, you can use those too.

Regards,
Steve A.

The Board helps those that help themselves.

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Unless you are using products that have predetermined addresses (is DS1307) then you can use anything you want I guess if you are using AVRs as slave devices.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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The I2C spec tells you exactly which addresses are reserved if you want to avoid them.

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atomicdog wrote:
The I2C spec tells you exactly which addresses are reserved if you want to avoid them.

Right, but I was wondering if there was any preferred subrange of the non-reserved addresses for self-assignment. To put it another way, do devices with factory-assigned addresses span the full range of available addresses, or do the addresses tend to congregate in certain ranges and avoid others?

Of course I can avoid the factory-assigned addresses of any devices I would use in a particular application, but if there are preferred ranges of addresses more likely to avoid such conflicts I might as well get in the habit of using them. But it's beginning to sound like there are no such preferred address ranges.

Mike

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I think it varies too much by the manufacture of devices that might be used to know. A good place to start might be to avoid the address range of the 24Cxxx type EEPROM series since their vary common.