sorry, Ignore my pre coffee comment. I understand now, you were taking about your design. Sheesh.
On Sun, Feb 26, 2023 at 8:23 AM Stephen Adolph <[email protected]> wrote: > Brian, If I understand your comment, I don't think you need an IC to do > rom selection. I think the DAR uses a rotary encoder. > When I first saw the DAR, I wondered about that. I'm pretty sure I found > the part at Digikey. Very good! > Steve > > On Sun, Feb 26, 2023 at 3:51 AM Brian White <[email protected]> wrote: > >> Gratuitous use of another chip just for 2 OR gates to implement a 4:2 >> encoder. It's all less efficient and less practical than the dial-a-rom, in >> that the dar holds 16 roms and doesn't need another ic, and the dar >> programming connection is even simpler and more robust. >> >> But it just amused me to have a direct selector without manually binary >> encoding dip switches because why not? And I didn't want it to require a >> tool to use either like a screwdriver. And of course I always want an open >> source option, and I'm not up to the task of coming up with an open source >> rex-alike but using a Lattice part and the open source toolchain. >> >> It's unfortunate timing but I had already started this at least 3 years >> ago but just never finished it. A non-working version has been sitting in >> that github since 2019. A few weeks ago I finally dusted it off and >> corrected my bonehead pinout error, dialled-in the programming connection >> so it works well (the holes are slightly closer together than the pins, and >> the pattern and amount of offset took some trial & error) and replaced dip >> switches with the slide switch & or gates. I had no idea the dar was in the >> works. Not that it would have stopped me, but I just mean to say this isn't >> a reaction. >> >> It's no competition anyway because only a very few people ever build >> these diy-only things. I want them to exist so the option is there, but >> almost no one actually employs it. So this is not touching anyone's sales. >> Besides, *16* roms. And of course really it's even sillier when rex exists >> which doesn't even need a programmer or adapter to load it's, what, 30? >> slots? But for other platforms 4 is plenty. There's only 2 roms total for >> the 600 for example. Still leaves 2 free slots for hacking. >> >> I just added the browser-friendly render of the schematic to the readme >> so you can see the bank-select. >> >> -- >> bkw >> >> On Sat, Feb 25, 2023, 8:18 PM Mike Stein <[email protected]> wrote: >> >>> How do you select among the 4 images? >>> >>> On Sat, Feb 25, 2023 at 6:50 PM Brian K. White <[email protected]> >>> wrote: >>> >>>> On 2/25/23 10:31, [email protected] wrote: >>>> > Morning all, >>>> > >>>> > I just made this video live this AM. The DARs for the Model T >>>> computers >>>> > have sold out already but my friend is making more. >>>> > >>>> > In this video we take a look at the ‘Dial-A-ROM’ a spiffy new >>>> multi-ROM >>>> > for vintage portable computers. It was designed by the same guy who >>>> did >>>> > the Backpack drive. First, we’ll learn how to use the Dial-A-ROM with >>>> > the ROM images that come preinstalled on it. Then we’ll see how to >>>> add >>>> > our own ROM images if we so desire. >>>> > >>>> > *https://youtu.be/CejyLsI0HIw <https://youtu.be/CejyLsI0HIw> >>>> > >>>> > Jeff Birt (Hey Birt!)* >>>> > >>>> >>>> And for the diy-er, I finally vetted these last week: >>>> https://github.com/bkw777/Teeprom/blob/master/4ROM.md >>>> >>>> -- >>>> bkw >>>> >>>>
