gnupic: Re: [gnupic] [ANN] Pikme PIC Bootloader (for 16F819 etc)
Subject:
Re: [gnupic] [ANN] Pikme PIC Bootloader (for 16F819 etc)
From:
John Sheahan ####@####.####
Date:
25 Jul 2006 23:03:11 +0100
Message-Id: <44C6951E.5050708@optushome.com.au>
Byron A Jeff wrote:
> Note that Wouter voices some concerns with trusting the PIC protection
> diodes to clamp and keep the part working properly. Frankly since a 10
> cent zener (well a 65 cent one if you buy from the RatShack) can easily
> do the job, why not use it?
>
I agree conservative design is good, but probably grossly overdone in
this particular case.
If the pin in question is an IO (not MCLR) you have the intrinsic well
diodes to clamp to vdd.vss for free. They are in addition to ESD
protection.
The external zener is likely to be slow enough (due to lead inductance)
to be of little benefit.
For mclr, its designed to handle Vpp, so should be safe enough too.
john
