Andy,

--- In sprog-dcc@..., "Andy" <andy2000@...> wrote:
>
> Hi Group
>
> I have just part built my SPROG kit. upto the USB testing section.
> unfortunately I struggling. two separate issues I think ??

They are probably related. In case anyone isn't aware, the kit
version is only available, to members, from MERG and is a slightly
older (but fully compatible) version.

>
> 1)
> My computer does not always recognise that the SPROG is attached,
but
> seems to be more reliable when i increase Vin to 17 to 18.5v. but
> still temperamental !!!

Vin should not make any difference, check thoroughly around the
voltage regulators (the LM317 and the 78L05).

>
> 2)
> Once recognised (not sure if this is normal) windows xp responds
with
> yellow box in bottom right corner :-
>
> "USB Device Not Recognized"
> "One of the USB devices attached to this computer has
malfunctioned"
> ".........."

Windows knows that you have connected something to the USB but cannot
complete the enumeration to identify exactly what, and load the
appropriate drivers. The former is a result of detecting the change
in bus loading, the latter by communicating with the device. Double
(and triple :-)) check component values and soldering around the
FT232 and the passive components between it and the USB connector. If
the 5V is out of spec, that would certainly be an issue. Also try the
troubleshooting app note AN232-02 from FTDI, although that assumes
access to an oscilloscope.

Hope this helps,

Andrew