Hi Olin,

On Wed, May 18, 2005 at 05:50:58PM -0400, Olin Lathrop wrote:
> Page 1: Power supplies.  The board will run from many cheap AC wall warts.
> There will be a 1.3mm socket for the same wall wart I use for the EasyProg
> and ProProg, plus screw posts for both AC and DC bare wire inputs.  The
> final rectified voltage needs to be about 11-30 volts.  DC supplies from 12
> to 30V will work fine.  A basic buck regulator makes 5.5V, which is linearly
> regulated to 5.0V with an LDO.  I've done this in another design and it
> worked very well.

As another poster mentioned, this power supply seems overly complicated. I
like flexability, but I think the prototype area could be used for
this. Most of my power supplies (I'm a hobbiest btw) are simple 78L05's or
LP2951 type chips. I haven't designed any commercial products, so my power
supply opinions might not be valid for anyone else. :)

> Page 4: Diagnostic LEDs.  These are uncommitted so that you can wire them to
> any signal you wish.  Each signal has two LEDs, one lit when the signal is
> high, the other when low.  This is useful for seeing short pulses when a
> single LED would othewise be in the on state.  It also avoids having to
> configure LED polarity.

Wow! This is a great concept! This would be very useful in debugging as
well.

> Page 5: Prototype area.  There will be uncommitted strips of 5 pads
> surrounded by bus lines, much like the common "protoboards".  The schematic
> is roughly laid out like the real board will be, except that there won't be
> a space every 10 pins.  That's just for my sanity in working with the
> schematic.  The pad strips and busses will be connected on the bottom layer,
> with the top being a ground plane flowing around the holes.  The top silk
> screen will also indicate how the holes are connected.

This sounds good. IMO, I think the prototype area should be about 3/4 to 1.5
the size of the board. That estimate is just a guess though. 

> Overall I intend most of that pats in the schematic to be pre-installed, and
> therefore surface mount.

All of my PIC circuits, so far, have been made using soldered point-to-point
wiring. Using a board like you have described would be great; my circuits
would look a bit better using a board like this. ;)

I like this idea. Especially, if it comes with nothing but the power supply
components installed. Olin, I like your ideas.

Take care, Matthew.

-- 
"This is not a scientific issue, it's a political issue," he said.
"There isn't a scientific issue about the validity of evolution. The
only issue is whether schoolchildren will learn real science or not."
          -- Adrian Melott
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