Usb prob

[bowler32]

Hi,

When I use the USB development kit it works ok, but when I try my own target board I get a message saying device not recognised. The only difference is my clock is 8MHz not 20MHz, I have changed the value of PPL from 5 to 2.

was:
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PPL5,CPUDIV1,VREGEN
#use delay(clock=48000000)

now:
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PPL2,CPUDIV1,VREGEN
#use delay(clock=48000000)

Thanks

[Ttelmah]

Try using a phase locked loop, rather than a private pilot's license!.
However the compiler should complain about this, so it is probably not the problem!.
Look very carefully at the connections to the USB plug. Bus them through with a meter. The commoest failing, is not getting the connections right here.

Best Wishes

[bowler32]

Thanks for the reply.

Sorry about the PPL I can't seem to type today, it is PLL in the program.
I have tested the connections about 5 times over the weekend thinking it was me and they are ok. My next possible solution it to just try a 20MHz clock but this is not ideal.
Anymore ideas would be very much welcome.

Thanks.

[Guest]

What capacitor, have you got on the Vusb pin?. Again, a lot of issues with this, but normally affecting reliability, rather than the initial connection.

Get a USB sniffer program, and look at what is actually happening. You should be able to see how far down the negotiations the system is getting.

Best Wishes

[bowler32]

Thanks for the capacitor suggestion. It now works.