AVR-Chat

Hi,

>  Everything seems to work fine, including ISP. But I did notice that when
> I brushed my finger on the ISP connector and at the same time touched the
> tab of a HV switching FET I'd get spontaneous resets.
>  This is a bit extreme, but I think the answer is that in a normal noise
> environment you can leave the parts out of the design. In a high noise
> situation put them in, or better yet disable the reset pin entirely after
> development is done (proper use of BOD is probably advised.)
>
> Sorry for only having anecdotal evidence.

    I was afraid to receive this kind of answer :-) It is one of the things 
that I hate most about data sheets... They tend to be non-conclusive in many 
aspects.

    On a 2 layers board the space taken from the res and cap is annoying. It 
is cheap but "disturbs" the board around and I hate to use parts that are 
not really needed..

    Have you tried to put a 100 nF Capacitor to ground or a 10K resistor to 
VCC and made the same test ? With the internal pullup the cap may be enough 
to cope with external noise...

Best regards,
Alexandre Guimaraes