I'm trying to get a DS1307 RTC up and running on the new P5 header on a rev 2 board. According to posts about the rev 2 board, the P5 is meant to be used for things like 3rd party RTC boards.
I've followed various tutorials on using I2C using 5v devices with the RPi. I've got the IC2 tools installed, and its showing i2c-0 and i2c-1 as valid busses with nothing active on either.
I've got a DS1307 board from ebay, which I've previously tested on an Arduino mega, so I know it should be working. I've connected it to the I2C pins on P5 header (pins 3&4). The RTC board had 3k3 resistors pulling SDA and SCL up to the 5v rail, so I removed these, and connected them via 1k9 resistors to the 3v3 rail. I've checked the voltages on each pin I've wired up and all look ok (0v is at 0v, 5v is at 5v, and SDA/SCL are high at 3.3v).
When I run i2cdetect -y 0 and ic2detect -y 1 I still get no devices showing (the DS1307 should be address 68 and theres also a AT24C32, but not sure what its address is). I've not yet tried the board on the P1 header, as its soldered direct to the P5 holes.
Any thoughts on what I may be missing.
What is a bit confusing to me is that the documentation on the eLinux wiki, that shows GPIO28 and GPIO29 as the I2C0 bus, (P5 pins 3&4). And it also says GPIO0 and GPIO1 are the I2C0 bus (present on the S5 connector). This applies since the rev 2 board, and that is what I am using.