diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/i2c/ten-bit-addresses | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/i2c/ten-bit-addresses')
-rw-r--r-- | Documentation/i2c/ten-bit-addresses | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/i2c/ten-bit-addresses b/Documentation/i2c/ten-bit-addresses new file mode 100644 index 0000000..200074f --- /dev/null +++ b/Documentation/i2c/ten-bit-addresses @@ -0,0 +1,22 @@ +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. |