On 7/11/19 10:02 AM, Kurt McCullum wrote:
Nice 3D printed option rom carrier too!
Thanks. Still dialing it in, but so far so good.
I just got an earlier version of the carrier in yesterday, and from that
I can at least say:
* the pcb fits in the carrier
* together the carrier and pcb fit in the socket and hold the pcb at the
right depth
* the material is resilient enough that it's actually usable for this
purpose
The early version I have doesn't yet have the snap wedges to lock the
pcb into the carrier, so I'm still waiting for a later order ship to
find out about that.
I didn't make the space for the pcb any taller than the nominal 1.6 mm
thickness of the pcb. I bet it really needs to be a bit taller than
1.6mm to allow a 1.6mm part to fit inside But I don't want it to be
loose at all either, so I just started there and we'll see what we see.
Once I have the pcb and carrier fitment good I'll post a blank version
somewhere so you can make up a board of your choice instead of either a
rex or a 28c256.
I don't know what else you might possibly put in the option rom socket
than a rom or a rom library machine that can pretend to be a rom (REX).
But, then again, who knows. Once it's easy to do, maybe then some kooky
ideas will turn up what to do with it. Maybe you can get a tpdd-alike in
there, which would be just sick. I have already used an arduino tpdd
that was physically small enough. Not only would it be better than
having something stuck onto the serial port on the outside, it would be
powered by the socket instead of needing a battery. It wouldn't
literally be a tpdd server because it wouldn't communicate by serial, so
I assume that would need it's own new dos.
Maybe a rom emulator/library like rex, but which has even more brains,
such that it can detect what kind of machine it's plugged in to, so the
same module could host roms for both 100 and 200, or maybe even other
things with different pinouts like 600 or Epson px-4 px-8.
Or something in between a plain rom and a rex, like a simply larger
plain rom with just dip switches to select partitions. Or maybe push
buttons and latching electronics, maybe even indicator lights, but point
being nothing remotely exotic or inscrutable either hardware or
software, and no compatibility problems with other exotic accessories
like PG Designs ram upgrade.
Or something that has brains, but it's all fully scrutable like arduino
sketches.
Or maybe it could be literally a tpdd server using the serial port and
existing off the shelf dosses. You could use the pcb simply to house and
power the arduino, and only have a ffc cable going out to the serial
port, and probably still have at least one plain rom loadable in there.
The arduino to serve up tpdd wouldn't have to touch the data pins, so a
plain rom could be on the same pcb completely separate from the arduino.
Or maybe just a pinout adapter that just erases the stupid pinout and
supplies an empty socket with a standard pinout.
But anything that has "rom" or even "tpdd" anywhere in the description
somehow just feels like I'm failing at imagination. Wifi? Bluetooth?
Most generic peripheral or comm hookups would seem to be better served
already by the serial & parallel ports, which exist exactly for those
kinds of purposes.
Maybe specialty stuff that's essentially a like an application with it's
own hardware support? like a game cartridge with it's own extra sound
hardware. But I was just thinking about a guitar tab & lyrics reader
app, with a tuner. A pcb in the rom socket could host the app, a library
of tabs much larger than 32k where only a little bit is paged into the
32k space at a time, and a mic, and maybe a frequency reference if the
M100 itself doesn't have anything accurate enough.
--
bkw
On Wed, Jul 10, 2019, at 11:28 PM, Brian K. White wrote:
I finally did the version of this that I had envisioned.
https://oshpark.com/shared_projects/Sk27mJwq
The idea here is you just buy a cheap modem cable for $2 and cut off the
9-pin. No dupont crimping, no backshell assembly, least possible strain
from stuff hanging off the 2x4 header in the tpdd. The tpdd-end only
needs heat-shrink and maybe some hot-glue. I think I actually prefer
that to making the pcb any larger to make a dedicated place for
strain-relief.
One thing not in the pics yet is, to get a polarity bump, I'll try
replacing the 2x4 header with a 2x3 standing on two in the middle,
flanked by two 1x2's. Should work fine and be less finnicky than trying
to glue something onto the top of the 2x4.
--
bkw
On 6/1/19 8:47 PM, Fugu ME100 wrote:
> I went for a slightly different solution and made a level shifter
> board that fits into the TPDD 8x2 plug on one end with a DB25 towards
> the Model T, then used an off the shelf straight through serial cable
> to connect the TPDD to the Model T. Works really well no need to
> crimp anything just all very straightforward soldering :)
>
> Did need to ‘extend’ the board a little to get the connector to fit
> properly into the TPDD. I used an edge solder approach as you can see
> (Hope the image is OK to attach?) I didn’t bother with a enclosure
> the board is really tiny, although thought about using shrink tubing.
> It could of been a DB9 but I had a lot of DB25s to use up :)
>
>
>
> From: M100 <[email protected]
> <mailto:[email protected]>> on behalf of Brian White
> <[email protected] <mailto:[email protected]>>
> Reply-To: <[email protected] <mailto:[email protected]>>
> Date: Saturday, June 1, 2019 at 5:14 PM
> To: <[email protected] <mailto:[email protected]>>
> Subject: Re: [M100] dsub 25 hood that fits
> <snip>
>
> Another idea is make a different pcb which goes on the tpdd end
> instead of the m100 end. A crimp-on 2x4 idc (he said, redundantly,
> given what idc stands for) plug does not fit in the hole in a
> tpdd, but maybe a female 2x4 pcb header does. If you could just
> extend a female pcb header to stick up off a pcb surface just a
> little more, then you could have a small pcb that sits flat
> against the back of the tpdd, and has a plug that sticks in to the
> tpdd. That would eliminate the *excruciating* process of crimping
> individual tiny dupont connector pins I'm using right now. Then
> just cut the db9 off a common modem cable and solder that to the
> pcb, and you have a full cable that was much easier to build, and
> which fits in a M100. (Rick's original cables were easy enough for
> him to build only because he used FB100 cables to provide the tpdd
> plugs. I'm going for more available parts.) Only remaining problem
> there is some sort of enclosure for the pcb. Maybe the 2x4 header
> can be a right-angle type, and so the pcb sticks out 90 degrees
> from the tpdd in line with the cable. Then, assuming the whole pcb
> is small so it doesn't stick out too far, and give it a little
> dog-bone shape, you could zip-tie the serial cable to it and
> enclose the whole thing in simple heat shrink. I don't know if you
> can get a right-angle header to stick out far enough from the side
> of a pcb to allow it to reach in to the pins in the tpdd though.
> And I don't think there's enough room for the pcb to extend inside
> the hole either.
>
>
> <snip>
