Thanks Gary, of course you are right. The DISK and RAM key works as you describe too.
Jeff From: M100 <[email protected]> On Behalf Of Gary Weber Sent: Sunday, February 26, 2023 1:51 PM To: [email protected] Cc: [email protected] Subject: Re: [M100] VIDEO - Dial-A-ROM for the Model T computers (and others) Hi Jeff. That's a fancy little unit! Great functionality for such an inexpensive device. One quick note about your TS-DOS uninstall portion: In the TS-DOS screen, the key label on F5 shows the actual current state, not what pressing the key would change it to. When you see "DOS-OFF", it means the DOS is unhooked. Pressing it so that it changes to DOS-ON actually means you've just hooked it into memory. You can verify the truth of my statement by having it show the "DOS-ON" status, and then drop into BASIC and type LFILES when you have a Backpack hooked up. On Sun, Feb 26, 2023 at 12:03 PM Brian K. White <[email protected] <mailto:[email protected]> > wrote: On 2/26/23 12:16, Mike Stein wrote: > Ah, got it; I was asking about switching it from the keyboard as the XR4 > does, not a physical switch. > > But if you're just talking about a small number of selections then tiny > diodes would probably work just as well and not require any power. I guess you're right, since it's only OR gates and positive logic, those could just as well be common cathode pairs of diodes, and they are available in a single 6-pin package, and it needs one fewer resistors because instead of pulling down the 3 inputs, you pull down the two outputs, though that doesn't really save me anything because I'm using a single 4-resistor part. It doesn't save much in absolute terms, like cost or real estate, but it still does remove a bit of power and trace routing and trades a fancier part for a more common and basic part. I'll try it. > m > > On Sun, Feb 26, 2023 at 9:52 AM Brian K. White <[email protected] > <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> >> wrote: > > On 2/26/23 08:23, Stephen Adolph 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. > > I understand that the dar uses a rotary encoder. > The slide switch needs the extra glue. > > I was responding to Mike's question "how does the bank select work?" > answer: gratuitous extra parts because I just wanted a slide switch. > > > > 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] > <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> > > > <mailto:[email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[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] > <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> > > > <mailto:[email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[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] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> > > <mailto:[email protected] <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> >>> wrote: > > > > On 2/25/23 10:31, [email protected] > <mailto:[email protected]> > <mailto:[email protected] <mailto:[email protected]> > > > <mailto:[email protected] > <mailto:[email protected]> > <mailto:[email protected] <mailto:[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> > > <https://youtu.be/CejyLsI0HIw > <https://youtu.be/CejyLsI0HIw>> <https://youtu.be/CejyLsI0HIw > <https://youtu.be/CejyLsI0HIw> > > <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 > <https://github.com/bkw777/Teeprom/blob/master/4ROM.md> > > > <https://github.com/bkw777/Teeprom/blob/master/4ROM.md > <https://github.com/bkw777/Teeprom/blob/master/4ROM.md>> > > > > -- > > bkw > > > > -- > bkw > -- bkw
