Looks like it's there for isolating the Vcc line from the MCLR line during 
ICSP.  Not sure why two though, but might guess that it has something to do 
with the reverse current limit?

There is another arrangement when the diode goes the other way (pointing 
towards Vcc), and there is a capacitor between the MCLR line and ground as 
well -- it's an RC startup delay, with the diode helping the capacitor 
discharge quickly after power off.

Cheers,
-Neil.


On Tuesday 19 April 2005 03:09 pm, Ake Hedman scribbled:
> I have seen some schematics with a PIC included  which have had two
> diodes on the MCLR pin connected
> like my mighty fine ;-)  ASCII schema below.
>
>                   VCC
>
>                     |    |  10K
>
>              ------------
>
>   Diod   V               V Diod
>
>
>               _____________________  MCLR
>
> What function does the diodes have?
>
> /Ake


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