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> Sean wrote:
> > 3) I have seen some negative comments about the multiple sockets
> > - and I wonder if Jason realises that I can buy ZIF sockets quite
> > cheaply.
>
> Even if you could get ZIF sockets for as cheap as LIF, they would
> take up more room on the board - about half an inch more length
> than LIF, plus space for the handle when it's down.
>
> > Is there any way we can have a 40 Pin WIDE ZIF socket accomodate
> > ALL available PICs?
>
> That's quite doable for programming only, but will inevitably
> result in some pins that need to be connected to Vdd/Vss for some
> chip sizes, but are normal I/O pins for others.  Not a problem for
> a programmer, since the unused I/O pins are inputs during
> programming, but it wouldn't be very good for prototyping to have
> some of your I/O permanently connected to the power supply...
>
> The main reason I didn't go for a single-socket design is that it
> couldn't give any sort of meaningful names to the breadboard
> connections - they would mean entirely different things depending
> on the size of chip installed.  HOWEVER, it has just occurred to me
> how to fix this - a single-socket programmer/prototyper would have
> to have some sort of personality module anyway, to route power to
> only the appropriate pins for any given chip size, and that could
> also handle routing all of the port pins to the appropriate pins on
> the breadboard connector!
>
> So, here's my current idea:
> * One 40-pin ZIF socket, plus the 6-pin ICSP connector as before.
> * A slot for a personality card, parallel to the ZIF - it looks
> like it will need about 80 pins.  Could be edge connector, dual-row
> header, SIMM, etc.
> * One personality card for each size of PIC - 8, 18, 28, 40 pin.
> They will primarily just consist of traces connecting the ZIF pins
> to the Designer's bus, plus one or two OSC connectors as
> appropriate for the PIC size.  The only actual component likely to
> be on the personality cards is a bypass cap for the target PIC,
> this is the closest it could possibly be mounted to the PIC under
> this scheme.  Cards other than the 40-pin would have silkscreen on
> the side facing the ZIF socket showing how the PIC should be
> aligned in the socket.
> * Since the personality cards are solely responsible for
> connections to the PIC, they could also contain a socket themselves
> rather than using the ZIF.
>  This would be useful for later development of cards for PLCC,
> SOIC, or other non-DIP PICs.

Congrats, you just invented CUMP.

- --Brendan

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