--As part of the process of packing up and moving my "stuff" I have been taking
--inventory of what I put in boxes as I pack them.

A tool that I find very nice for this kind of work is the old Radio Shack
TRS-80 Model-100. This is a small, easily carried around, battery powered,
instant on/off (no drives) portable computer with a good size display and a
full size keyboard - all this in a package measuring 11.5" by 8.5" by 1.5"
- you can use it about as easily as a piece of paper when taking notes!

I've created a couple of tools to help work with the Model-100:

 M100   transfer files from/to the Model-100 from a PC (incl BASIC programs)
 ASM100 assemble 8085 machine language code, and generate a BASIC program to
    place it into Model-100 memory.
 ASM85  My 8085 cross assembler (used by ASM100 to assemble the code)
 HEXFMT Manipulate .HEX upload/download files

For help with these, run with no operands (ASM85/HEXFMT my XASM package docs)

Unfortunately I have't ported my communications functions over to Windows/LCC,
so these run under DOS. They do however work well in Windows with DOSBOX.

In "figuring out" some undocumented things of the Model-100, I wrote a
simple Machine language MONITOR to run on the Model-100. See M100MON.ASM
-- I wanted to port my full MON85 (breakpts, disasm, step and more)
-- but the Model-100 ROM does not appear to have any means of accessing
-- any RST vector (MON85 uses 1-byte RST for breakpts and step)

Complete Model-100 documents can be downloaded from: Dave's Old Computers
   http://dunfield.classiccmp.org/kyocera/index.htm


Note on batteries:
------------------
The Model-100 uses 4 AA cells. Typical "dry cells" seems to get me 10-20 hours.
This might seem "good and long" but it often sits to the side switched on while
I'm packing. So battery life can be a bit problematic.

Rechargable's don't work well either. "Dry cells" give 1.5V each, so the 4-pack
totals 6V.  The Model-100s "low battery" alert comes on about 5V...  NiCad/NMIH
rechargables give 1.2V per cell, making a 4-pack quickly settle to a nominal
4.8V - the Model-100 doesn't take well to this!

5x1.2V = 6V, so 5 NiCads would run it fine, but there are only 4 slots!

One of my Model-100s had the battery contacts removed and the door glued shut
(I think former owner got tired of employees leaving leaking dead cells in it).

So I added a connector to access the leads and made an external pack holding 5
cells (can be done in a small straight tube just the width of the Model-100).

Freshly charged NiCads can "ride" a bit higher than 1.2V so I added a diode on
the battery leads. This protects against reverse batteries, AND gives about a
0.7V drop. This gives my pack about 5.3v when nearly "out" and 6.2v when just
off the charger. This works very well and runs for days on a charge.

To see my homebuilt pack, look at M100BAT.JPG

Dave Dunfield   -   https://dunfield.themindfactory.com
