Hello!

I'd like to interface my butterfly to the Devantech CMPS03 Compass module, which is an I2C slave device. Since the butterfly has a nice LCD, it will be nice to be able to display the compass output on it.

I've interfaced to the Compass before with the CodeVision I2C library and a Mega128, but I'm trying to move over to WinAVR.

Since the Mega169 has the USI, rather than the TWI hardware, I've been struggling to find any avr-gcc code that implements I2C Master functionality with the USI hardware.

I've read the technote on the Atmel site regarding implementing I2C with the USI hardware, but I can't seem to find even the IAR example code, much less avr-gcc code.

Has anyone seen any avr-gcc code that implements I2C with the USI hardware?

I'm leaning toward using the Peter Fleury all-software I2C implementation, but it seems a shame not to use the USI hardware...

Thanks!

Tim White