Re: [avr-chat] avrdude : chip not responding

[Bob Paddock]

On Friday 02 September 2005 04:52 am, Erik Christiansen wrote:

> I wouldn't worry too much about a little rosin residue.

I would.  It can trap other contaminates.  Some rosins are also extremely 
corrosive if left on the board for any length of time.  I have seen pins 
eaten away after a few months, when production forgot to clean the boards.

> It doesn't  conduct that well. How bad is the crosstalk on the long cable
> when the chip _is_ connected? 

Any ringing on the SCK line may prevent the part from programming.
The AVR sees them as extra clock cycles and the data that it thinks it is 
getting is not the same as the data you are sending.  Longer cables make the 
problem worse.  If you can not fix the problem on the source end, or use a 
shorter cable, try some small value resistors in series with the signals on 
the AVR end of the cable.  [I have not been following this thread that 
closely, someone else might have already suggested that, as I recall 
something about 33 Ohms.]