[sdiy] Strange uController behaviour (slightly OT)

[Ken Stone]

>Now the uC works absolutely correct even with black tape on the window, as
>this normally should be the case.
>
>It seems, that the light falling on the chip in the earlier setup was
>cancelling the effect of noise picked up through the long unconnected wires.

I saw a similar effect with an Eprom many years ago - It was part of a
prototype micro my boss was working on. It worked in sunlight, but shadow
stopped it cold. He couldn't find the fault so I looked it over. One of the
address lines was broken. The sunlight was providing enough influence to
allow the eprom to address correctly by a very weak capacitive coupling. 

Electronics can be weird.

Ken
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au  
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
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