we got problems connecting the HMC5843 Magnetometer to the PIC.
It seems to have data ready (Testpoint Pin19 is high), but it does not acknowledge the i2c_write(0x3D).
we are working on a Dual Power circuit from the PIC18F4550-I/ML datasheet with the difference that we switched VBus and VSelf, so that the usb bus replaces the power of the battery.