The I2C is a simple communication standard intended to move small amounts of data a few inches between chips. Please See I2C Wikipedia page for additional information.

I2C addresses

Note that I2C addresses are 7 bit. The last bit, which is not part of the address, indicates whether this is a read or write operation. So "0001 000x" is 0x8, not 0x10.

Neo1973

On the Neo1973, we currently use the following addresses on the I2C bus:

Device	I2C address
PCF50606	0001 000x
WM8753L	0011 010x
LM4857	1111 100x

I2C Testpoints

From: Andy Green <andy@openmoko.com>
To: openmoko-devel <openmoko-devel@lists.openmoko.org>
Date: Wed, 02 Jul 2008 09:11:03 +0100

If you pop the top facia, I2C is available from two testpoints near the debug connector. GND is not on a testpoint there but the mounting holes at the bottom and you can grab it from a capacitor under the battery on the right of the picture too.