I think Eric has a very good point. There are very few components that are
applicable to all PIC projects. An idea I am toying around with is an MCU
motherboard. This motherboard would have very little on it and would
basically only serve to provide a low pin count interface to the MCU and the
ability to plug in multiple external devices. To minimize pins used (so you
can directly interface the devices that need to be accessed quickly) you
would almost certainly want a serial interface. A bus would also remove the
single external interupt problem as you could implement a P.I.C.
(Programmable Interrupt Controller) on the bus.

The main design limitation would be the software overhead. You can alleviate
this problem on higher mid-range PICs by making the interface SPI
compatible. However as low end (and some mid end) PICs don't have hardware
SPI the ease of software implementation would still be an issue.

If you add an FPGA and use this for all interfacing then you might be able
to offload some of the processing to it (at the very least you could use it
to add FIFO's to the Serial to Parallel inteface).

The other obstacle is size. In prorotyping this isn't an issue but it would
be nice to be able to take "off the shelf" (your own shelf) units and
quickly connect them to create a custom unit and only have to write code
specific to the application.

Thomas Brandon.

BTW: Yes, this is a fair bit like the Simmstick products Dontronics
(www.dontronics.com) sells.

----- Original Message -----
From: Eric Smith
<SNIP>
> It looks to me like a lot of them are mediocre suggestions.  By which I
mean,
> suggestions that will be great for only a few people and useless for the
> majority, and things that are easy enough for a person to wire up on their
> own.  I mean, how much trouble is it really to wire up an EEPROM or an
extra
> voltage regulator?  But that space (and cost) is just wasted if your
> application doesn't happen to need those.
>
> How about having your original features plus a prototype area?
>
> The only suggestions I thought were of very general applicability were the
> ICD/ICSP connectors and the EIA-232 interface.  And I may be biased in the
> latter case because about 2/3 of the projects I build use a serial
interface.
> Some people I know rarely use them.