where to fault find with 24 ff:

[billium]

I have a standard circuit, AtMega 328 or 168 with PD2 (INT0) D+ and PD3 D- with a 1k5 pull up on D- & 1M pull down on D+ fed with 3V3.

With minimal forever{ led on usbPoll led off} and debug level set to 2.

All I get is 24 ff: s i.e. reset condition. The pc is unable to enumerate (as though the AVR wasn't present but the 1k5 was).

I can see the PC's USB comms on pins PD2 & PD3 on an scope o.k.

Anybody give any tips on fault finding from here?

Many Thanks

[vouvoume]

Wrong fuses and so wrong clock?

[billium]

Unlikely as the serial port works o.k. May be using at 3V instead of 5V for 12MHz but I'm assuming it can handle 12MHz at 3.3V, will test later.

[billium]

I was following the Code and Life examples, with the above errors, so I started again using the examples with the download and it all works now even 3V @ 12MHz. May investigate debugging later. I'll learn the pseudo interrupts now.