[sdiy] Arduino schem - diode in series with R at reset pin?

[Gordonjcp]

On Thu, Apr 23, 2015 at 07:27:34AM -0700, Justin Owen wrote:
> Hello,
> 
> http://i.stack.imgur.com/cPCB4.png
> 
> Some of the Arduino schematics have a diode in parallel with the normal R to VRef on the Reset Pin (Pin 1 in the above link).
> 
> Can anyone explain what the diode is doing and why it only seems to be on Arduino schems?
> 
> FYI, I'm looking specifically at using the Atmega 328P in a non-Arduino, stand-alone circuit.
> 

It clamps external voltages on the reset pin to the 5V rail.

-- 
Gordonjcp MM0YEQ