Hello Jeroen,
We haven't heard from you lately.?? The model 100 bus and option ROM port
are useful, as are the bar code reader port, etc.
I highly recommend that you ensure that your sound emulation is good --
music/sound processing is one of the "killer apps" for me.?? :-)
On 6/2/2018 4:04 AM, Jeroen Domburg wrote:
Hi all,
TL;DR: I'm building a tiny M102.
Let me first re-introduce myself on this list. Hi, I'm Jeroen, also
known as Sprite_tm on the wider Internets. I was on this list around
2001, which is way longer ago than I thought it was. At that time, I
wanted to see if I could convert the Olivetti M10 I bought at a flea
market to accept M100 roms. I actually succeeded: took but a small
conversion routine for the different keyboard layout to make the M100
ROM work in the M10. Talked to Rick Hanson at that time to ask if he
could send me some ROM images. I'm sad to read he has passed a while
ago... always seemed like such a pleasant guy in the email conversations.
Anyway, why am I back? I nowadays live in Shanghai, doing electronics
stuff, and recently I directed my hobby into re-making the machines I
enjoyed back in the days This already has resulted in a matchbox-sized
Game Boy
(https://hackaday.com/2016/11/28/tiniest-game-boy-hides-in-your-pocket/),
and a tiny Macintosh Plus (http://spritesmods.com/?art=minimacplus).
Now, I decided to see if I could do something similar to this: make a
tiny version of the TRS80 Model 100 or 102 (haven't decided yet). The
plan is to use a newfangled low-power STM32 ARM processor for this; the
processors that are around nowadays are actually pretty quick (80MHz),
have a fair amount of RAM (64K, twice what the M100 had at maximum
capacity!) and are even more efficient than the 80c85 (a few micro-amps
per megahertz). Also, they have a bunch of peripherals integrated, so I
can get away with not much more than that chip.
Here in China, it's actually pretty easy to get the basic parts for
this. The most important part, obviously, are the LCD and the keys, so I
decided to start there. I found a nice and tiny (and cheap!) 256x64
display, which could be a nice stand-in for the 240x64 LCD in the
original hardware. To test it out, I connected it to my laptop and did a
hack to get VirtualT outputting data to it:
http://j0h.nl/AqkB
(And yes, it's a bad picture... I shouldn't take pics in bad lighting
around midnight, I guess. For reference, the purple thing underneath is
a credit-card sized metro transportation card.)
For the keyboard, I decided to go with the bare metal domes you
sometimes see in somewhat cheap-ish but still ok feeling keyboards for
remote controls, old-school brick phones etc. The nice thing is that
these domes are about US$0.005 each. The bad thing is that they need a
specific PCB layout to work... so I had to make a PCB for this. Luckily,
this is also cheap-ish here, although the gold-plating set me back a few
quid more than I'd liked, and I'll probably re-spin these because they
have a few mistakes in them. The keyboard part seems to work, however.
Here it is while building it up:
http://j0h.nl/AaoB
And here is where I am now. I've used kapton to hold down the rubber
domes, and I can actually already type on this; the domes are all well
worth the half a cent each I paid for them, nice and clicky. I also
installed the microprocessor and USB-port, and at this stage I can blink
the power LED, so at least the hardware seems mostly okay.
http://j0h.nl/AKsB
http://j0h.nl/B6wB
So, why am I posting this? I dunno, I like writing about this I guess,
and maybe you guys have some good ideas for continuing. I'm pretty sure
I can write the emulator without too much effort. The USB port is
probably going to be used for a serial port; I may also use it to upload
things like option ROMs. (The microcontroller has 256K of flash, so I
should be able to fit a few.) I also need to think about a case: I have
a pretty kick-ass Formlabs 3d-printer at work, but my workshop does not
have many mechanical tools. In the end, I'll also add a LiIon battery: a
tiny 150mAh one probably is long enough to let the entire thing actively
work for 80 hours or so.
Hope a project like this is appreciated on this list; if not, I'll
happily keep working on this in silence. My experience with the M100 is
nil, however, so if you people see things I missed to make it an even
better M102 replica, I'd love to hear this.
Cheers,
Jeroen
