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- The I2C protocol knows about two kinds of device addresses: normal 7 bit
- addresses, and an extended set of 10 bit addresses. The sets of addresses
- do not intersect: the 7 bit address 0x10 is not the same as the 10 bit
- address 0x10 (though a single device could respond to both of them). You
- select a 10 bit address by adding an extra byte after the address
- byte:
- S Addr7 Rd/Wr ....
- becomes
- S 11110 Addr10 Rd/Wr
- S is the start bit, Rd/Wr the read/write bit, and if you count the number
- of bits, you will see the there are 8 after the S bit for 7 bit addresses,
- and 16 after the S bit for 10 bit addresses.
- WARNING! The current 10 bit address support is EXPERIMENTAL. There are
- several places in the code that will cause SEVERE PROBLEMS with 10 bit
- addresses, even though there is some basic handling and hooks. Also,
- almost no supported adapter handles the 10 bit addresses correctly.
- As soon as a real 10 bit address device is spotted 'in the wild', we
- can and will add proper support. Right now, 10 bit address devices
- are defined by the I2C protocol, but we have never seen a single device
- which supports them.
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