Have you already settled on the sockets/connectors yet??  What you 
really need to do is connect GROUND first, then power, THEN signals.  I 
know they make connectors that have longer pins for ground and power, so 
that those connections are made first, then data lines come into play. 
 Those would be the obvious choice, if you can pull it off!

Good luck!
Dennis

Jinx wrote:

>I'm working on a system that ideally would be a PIC motherboard
>that has sockets for PIC-based daughterboards, PC fashion
>
>Comms between all PICs would be I2C, and they will share a
>common data buss and IRQ system. Also a Plug And Play type
>detection system so the MB knows when a new DB has been
>attached
>
>Now, the system itself should work out fine, but it's quite possible
>that a DB can be plugged into the powered-up MB. As other DBs
>will be working it's just not possible to turn the power off
>
>So, the problem is, how to protect devices from damage at the
>time of insertion, or even removal too possibly. Or even is any
>protection necessary at all ? (I suspect it would be wise)
>
>Some options considered -
>
>Small slide switch for DB Vcc, turned on after DB is inserted
>
>Resistors or some other clamp for all DB connections (would
>mess up I2C ?)
>
>Somehow guarantee that Vss connects first - then what ?
>
>MB-mounted buffers (eg 74HC573s) that are enabled by
>initialisation of DB
>
>Any thoughts ?
>
>TIA
>
>===============================================
>If you aren't part of the solution, you're part of the precipitate
>
>  
>

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