| 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. |
