Diode an Reset

-macht reset-flanke knackiger

Mark schrieb:
> Hallo zusammen,
>
> ich habe mir den Schaltplan vom Arduino Mini mal als Referenz geöffnet.
> Hier habe ich gesehen das in der Reset Leitung eine doppel Diode BAV70
> eingesetzt ist.
> Ausschnitt des Plans ist im Anhang, das erstbeste Datenblatt der Diode
> ist unten verlinkt.
> Kann mir jemand verraten welchen Zweck dies erfüllt?!
>
> Gruß
> Mark
>
> https://assets.nexperia.com/documents/data-sheet/BAV70_SER.pdf

Denk mal nach was mit der Ladung in dem reset-C passiert wenn die 5V 
zusammenbrechen und welche Auswirkungen das auf den Chip haben könnte - 
sowohl als auch.

MiWi schrieb:
> Denk mal nach was mit der Ladung in dem reset-C

?ich seh grad keinen C am Reset?

http://forum.arduino.cc/index.php?topic=86389.0

The change was to add a diode wired from +5vdc to the reset pin, cathode 
to +5vdc. The prior auto-reset wiring design could cause an intermittent 
latch-up problem when auto-reset was activated. This 'latch-up' problem 
could effect most  prior arduino boards, not just the Uno boards, but 
was a little more prevalent when the Uno R2 design added a pull-down 
resistor on the 8u2 reset signal line. We never did find out why they 
added that resistor in the R2 design. Didn't really matter because we 
could duplicate the symptom on boards prior to R2, just not as 
frequently. There was a long post on this forum about this problem and I 
spend some time with others helping to try and verify if it was a real 
problem or not. It was real but pretty difficult to demonstrate in a 
repeatable manner. The problem was that the capacitance coupled reset 
pulse was sometimes triggering the arduino reset function into 
activating into it's high-voltage programming mode by creating a +10vdc 
pulse to the reset pin, rather then just a standard reset. Again it was 
not a common fault that everyone would experience as a lot depended on 
if a load was also wired to some of the I/O pins, like a pull-up or 
pull-down resistor, I forget which and which pins were most likely to 
help trigger the internal chip conditions needed to reproduce to the 
symptom.