N900 Hardware Bus I2c

I2C is a simple serial bus, used in many devices.

Hardware

Bus 1

• 0x48 0x49 0x4a 0x4b Gaia/chipset

Bus 2

• 0x18 0x19 Audio codec
• 0x29 N900 light meter
• 0x30 N900 Hardware Flash Torch
• 0x32 N900 Hardware LED
• 0x60 N900 headphone amplifier
• 0x63 N900 Hardware FM Radio Transmitter
• 0x55 N900 Hardware Charge Meter
• 0x6B N900 Hardware Battery Charger
• 0x10 VGA Camera (control)

Bus 3

• 0x0c Lens focus
• 0x1d Accelerometer
• 0x22 FM Receiver
• 0x3e Front Camera (control)

Bus ?

• 0x? GPS

Software

The N900 software driving I2C comes in three flavors.

Firstly, there are a large number of kernel drivers.

Then, there are a small number of devices 'bit banged' through I2C ioctls - BME for example does this with the charge meter and battery charger.

Finally, there are probably some I2C components in the Rapuyama and assorted cellphone/GPS hardware. These are not visible to the casual developer. (you have to open the N900 and probe stuff, or hack the phone firmware).