oh yeah... looking at the schematic again I forgot the actual function of the 3 /OE pins is still a question until actually tried.
So it's not quite time yet to claim 200 has this option that 100 and 102 have had for a few years. With the one pin being connected directly to A15 according to the service manual, I implemented that pin as active high. But until I actually try it, who knows? The schematic claims it's an active low /CE by labelling it that way. Yet... A15. `\_(oo)_/' bkw On Sun, Feb 26, 2023, 4:56 AM Brian White <b.kenyo...@gmail.com> wrote: > It still works. I use it. And anyone can build themselves a new one any > time from my re-spin plans, it just hasn't changed and probably never will > because I am not up to picking apart the firmware to hack on it nor write a > new one. It's Steve's last version. > > The only advancement is I made adapter boards for model 200 recently like > I had for 100 & 102 already, where the board includes a copy of a standard > rom so that it functions just like the original rom, but also provides a > solderless connection out to rex and back so that you can boot from the rex > or boot from internal without having to open the case again. And the > connections are all dupont jumper wires, so installable/removable without > soldering, and without blocking the original socket preventing having an > internal main rom. > > Some weeks ago when we were talking about the weird 8k chip in the 200, I > made a board for that. So now 200 also has this option to keep an internal > rom and still boot from rex. For the main 32k chip in the 200, you just use > the same one as 102. At the time we all decided based on the data sheets > that if all you wanted to do was replace that 8k chip, you should be able > to just use a normal 27C64, but I decided to actually implement the extra > control pin with a few gates just to be sure. > > I have built and programmed that new board so I at least know the > programing jumper setting works, but have not tried installing it yet. > github.com/bkw777/aDIPters#flexrom_200_m13 > > It's kind of wildly impractical. These small eeprom are getting stupid > expensive. I'm afraid to add up the cost of all the bits to make a rex > classic and these two rom adapter boards to make a 200 with rex classic and > still usable internal main rom. I mean I have already got all those bits, > but I just mean I don't want to find out explicitly just how dumb it is. ;) > > But I do love my 100 and 102 with the same option. I switch between stock > internal main rom with no rex, like when testing that ram+ or pgdesigns > ram, rex classic software main rom, rexcpm, and back etc any time without > opening the case any more. I love it. > > And it's all just sockets and dupont pin connectors. I could put the > original stock rom back in any time. I could also ditch the jumper wires to > rex yet still use the non-original main rom by just installing a jumper on > the pins on the board in place of the wires. I could also still update the > rom on the board. That would require opening the case again but no > soldering. > > bkw > > On Sun, Feb 26, 2023, 12:46 AM Mike Stein <mhs.st...@gmail.com> wrote: > >> Yeah, the XR4 would certainly expand the options (pun intended) but I >> never quite figured out how they selected among the images; I did work out >> another solution and started building a 16MB RAM expansion but never >> actually finished or tested any of it. Things like REX, the Backpack and >> the Dial-a-ROM are a lot easier ;-) >> >> The issue is that when TS-DOS is in (the single) ROM space it would get >> clobbered by loading another ROM image there; I'll have to have another >> look at it all, including the EME tools, to see how it might work. Am I >> missing something? >> >> BTW, I haven't used my REX in years; AFAIR it's the original version with >> the System ROM replacement option and I guess there's not much support for >> that these days? >> >> m >> >> On Sun, Feb 26, 2023 at 12:14 AM Stephen Adolph <twospru...@gmail.com> >> wrote: >> >>> Mike, not sure I follow. >>> You know you can have multiple ram spaces in option locations. Like xr4. >>> Could an xr4 do what you want? >>> >>> Xr4 was a tidy solution. Needed a few wires to make it work. >>> >>> I guess I don't understand why tsdos is not compatible with option ram? >>> Seems like it is, just like any other rom program? >>> >>> >>> >>> On Sunday, February 26, 2023, Mike Stein <mhs.st...@gmail.com> wrote: >>> >>>> As you may remember, years ago I designed an adapter that let you put >>>> both the system image and an option ROM image into a single chip that >>>> replaced the System ROM, both the standard (new) or non-standard (old) >>>> version; some folks on here may even still have one in their M100, probably >>>> loaded with TS-DOS. >>>> >>>> In another M100 I replaced the option ROM with RAM and load/save/copy >>>> etc. various ROM images using the EME extRAM tools, but of course I can't >>>> have TS-DOS in the same memory area as the option ROMs. >>>> >>>> The Dial-a-ROM and REX are certainly excellent solutions, but I'd still >>>> like to make the Option RAM concept compatible with TS-DOS, even if I have >>>> to add or reuse a physical switch to select between RAM and ROM. Any other >>>> ideas? >>>> >>>> m >>>> >>>> >>>> >>>> On Sat, Feb 25, 2023 at 11:26 PM John R. Hogerhuis <jho...@pobox.com> >>>> wrote: >>>> >>>>> >>>>> >>>>> On Sat, Feb 25, 2023, 8:18 PM Mike Stein <mhs.st...@gmail.com> wrote: >>>>> >>>>>> Yeah, I guess everybody has TS-DOS in ROM one way or another these >>>>>> days; I've thought about putting it in the system ROM instead of the >>>>>> Scheduler and Address Book, but removing them doesn't really free up much >>>>>> space; maybe Teeny would fit... >>>>>> >>>>>> >>>>> Scheduler and address book are a very simple "grep" type utility >>>>> serving as a simple database. I feel they are too clever and minimalist a >>>>> solution to remove :-) plus there are programs that let you use this >>>>> search >>>>> facility on any text file. >>>>> >>>>> -- John. >>>>> >>>>>> >>>>>>
