PIC18F1220 Debug problem

Hello,
i use PIC18F1220 but ICD2 don't enter in DEBUG mode
(program-mode is ok)
The settings are:
INTRC, port on RA5 and RA6
fail safe DISABLE
internal/ext switch osc DISABLE

and in firmware
OSCCON=B'01101111' (4MHz)

When go on debug, the ICD2 wait 2-3 minutes

Do You have any suggest for confing-bits and firmware setup?

Thanks
Emanuele

 

When I have had problems like this it has usually been because of circuit
loading on one or more of the ICD lines. Make sure Vpp can be raised to the
programming level (about 12V), and the clock and data lines must be free to
allow fast and clean digital signals. Also, make sure your clock is running
properly.

Paul