Does anyone have any experience using USB on the ATmega32U4 configured with the internal 8MHz oscillator clock source?
I am unable to communicate with the ATmega8 via USB.
My computer (Mac with OS X) does indicate that my board is connected.
I am using an Arduino Uno as a programmer via the ISP interface.
I can successfully burn a boot loader into the chip whilst setting the fuses as required.
My board seems to operate ok and simple test code can be uploaded to it (via the Arduino ISP) and it works as expected.
If the chip is programmed with the fuses set to output the clock on Port C pin 7, then a waveform extremely close to 8MHz is seen.
I have tried setting the LSM bit in UDCON to force low speed USB and this is reported as 1.5MHz by the Computer.
If I try and upload code via the USB connection then the programming fails saying it can't find the device on the port.
Do I have to use a special/modified boot loader to use the internal RC?
Is there anything specific that I have to do in order to get the USB working?
Is there something really basic that I have missed?
Any other suggestions most welcome.
Many thanks in advance...