"The Broadcom Serial Controller (BSC) controller is a master, fast-mode (400Kb/s) BSC controller. The Broadcom Serial Control bus is a proprietary bus compliant with the Philips® I2C bus/interface version 2.1 January 2000." BCM2835 ARM Peripherals

I2C on Rev1 P1 Header

The Raspberry Pi has I2C functionality available at GPIO00, SDA and GPI01, SCL.

             _______
 3V3        |  1  2 | 5V
 SDA (BSC0) |  3  4 | DNC
 SCL (BSC0) |  5  6 | GND
 GPIO04     |  7  8 | GPIO14
 DNC        |  9 10 | GPIO15
 GPIO17     | 11 12 | GPIO18
 GPIO21     | 13 14 | DNC
 GPIO22     | 15 16 | GPIO23
 DNC        | 17 18 | GPIO24
 GPIO10     | 19 20 | DNC
 GPIO09     | 21 22 | GPIO25
 GPIO11     | 23 24 | GPIO08
 DNC        | 25 26 | GPIO07
             _______
 

I2C on Rev2 P1 Header

The Raspberry Pi has I2C functionality available at GPIO02, SDA and GPI03, SCL.

             _______
 3V3        |  1  2 | 5V
 SDA (BSC1) |  3  4 | 5V
 SCL (BSC1) |  5  6 | GND
 GPIO04     |  7  8 | GPIO14
 GND        |  9 10 | GPIO15
 GPIO17     | 11 12 | GPIO18
 GPIO27     | 13 14 | GND
 GPIO22     | 15 16 | GPIO23
 3V3        | 17 18 | GPIO24
 GPIO10     | 19 20 | GND
 GPIO09     | 21 22 | GPIO25
 GPIO11     | 23 24 | GPIO08
 GND        | 25 26 | GPIO07
             _______
 

PCB Revisions

Note

This library should automatically detect the correct BSC module to use. Since the pins for both revisions are physically located in the same spot on the header, this should be transparent to the user.