Re: [Usbpicprog-technical] PIC18F1220 VPP question

[Frans S. <fra...@gm...>]

Dear Goncalo,

Well, it is difficult to say anything useful about this. Of course VPP
shouldn't go to 8V, but there can be many causes.
First of all, have you tried other target processors, and do they get
the normal ~12V VPP?
If others do work, you have ruled out the circuitry on the usbpicprog
hardware. If not, there might be a wrong soldered connection on the
usbpicprog hardware, or a connection with a higher resistance. But I
don't think that is the case if the voltage does go to 12V with an open
circuit.

Secondly, I would like to know how you connected the 18F1220. Did you
only connect usbpicprog, or is there any other circuit on the target board?

A last option might be a faulty 18F1220, have you tried a second one?

Kind regards,

Frans Schreuder

On 06/20/2010 11:45 PM, Goncalo Costa wrote:
> Hi,
>
> I'm trying to program a PIC18F1220, but when I connect the programmer
> to the PIC, VPP goes 8V.
> When I leave VPP open it goes 12.
> Any sugestions?
> Ideas?
>
> Thanks
>
> Goncalo
>
>