Yeah it can actually be done with a standard dip in a pcb adapter. The pins have to be squished in tight to the chip and there is just barely room, but it does work, because I have an old commercial rom that was made that way.
https://goo.gl/photos/k29KGbCxZ5jQFqgA8 There isn't one of those up on oshpark but it would be pretty simple to make. One advantage to that over these others is it allows for a nice neat key tab to stick out of one end of the board so you can't plug it in backwards, because the extraction ribbon is trapped under the dip chip instead of under the entire board. The 3 options I know of today are REX, and 2 different simple eprom adapter boards. REX is a pretty fancy thing that can hold 30 or so roms or ram backup images or even a couple alternative main roms if you're willing to solder a little wiring to the inside of the M100. And you can load and unload rom images and ram backup images all from software right on the m100. It's possible to make a REX for yourself. All parts are orderable, all necessary files are available for download thanks to Steven Adolph putting them up recently, and you can do it with an ordinary solder pencil, no reflow oven or anything. It's not exactly trivial to build and program, but it's pretty wicked when you do finally have it. http://tandy.wiki/index.php/REX The other 2 options are dirt simple by comparison, both simpler to build and simpler to use, but also they only do one simple thing. http://tandy.wiki/index.php/FigTronix There is also a main rom adapter there. It works but it's a whole other conversation I'll skip for now. ;) The two types of option rom adapters each have pros & cons. The all around best choice I think (between the 2 FigTroniX boards) is the socketed plcc one. It's finnickier to build because you have to use solder paste and hot air and kind of cross your fingers. And it requires sanding down the outside of the plcc socket which is just kludgy. But after that, It's more convenient to use in a few ways. You can carry one adapter and a fistfull of roms and switch between roms on the go. You can even store them right in the cavity where the option rom socket is, though you still need to carry a plcc extractor somewhere else anyway. And it's simple to program those plccs since they pop out of the m100 adapter. The SOIC board is easier to build in one sense, because you can use a regular pencil instead of hot air. You can see and reach every pin normally. But then you have a chip soldered permanently to a board that has an oddball pinout, AND an oddball physical pin connection. To reprogram that board, you need to use one of three possible methods detailed on that page. None are the end of the world, but it's just simpler with the bare plcc that pops out by itself and can pop into a standard programmer adapter. Mike Stein also has a neat board that does a kind of odd in between. You install it inside the M100 in place of the main rom, and it allows you to replace the main rom with either a different main rom, a permanently installed option rom, or both at the same time. If you use the option rom feature, it conflicts with the option rom socket though, so you'd have to keep that empty, and you'd have to open up the case to rewrite different roms. https://www.oshpark.com/shared_projects/Kil9S1ya -- bkw On Mar 17, 2017 6:01 PM, "MikeS" <[email protected]> wrote: > As I said, Brian White knows all about these adapters and also has a > Facebook section describing them; I expect he'll join the discussion soon. > > I think there were three different versions, using different (E)EPROMs and > programming adapters; here's another one: > > https://oshpark.com/shared_projects/m3Ugar47 > > ISTR the first version used a standard DIP chip, but I can't find it on > OshPark any longer. > > m > > ----- Original Message ----- > *From:* Bryan Ard <[email protected]> > *To:* Model 100 Discussion <[email protected]> > *Sent:* Friday, March 17, 2017 5:35 PM > *Subject:* Re: [M100] Help Imaging a ROM > > Would that be this one? https://oshpark.com/shared_projects/LfdyAK6a > > On Fri, Mar 17, 2017 at 11:55 AM, Mike Stein <[email protected]> wrote: > >> >> ----- Original Message ----- >> From: Bryan Ard >> To: Model 100 Discussion >> Sent: Friday, March 17, 2017 9:22 AM >> Subject: Re: [M100] Help Imaging a ROM >> >> >> > Any hints on building boards to drop new option roms into the 102? >> >> I expect Brian W will tell you more, but meanwhile check out OSH Park: >> https://oshpark.com/shared_projects >> >> Search for "m100 option rom"; there are several revisions. >> >> m >> >> >> >> >
