68kMLA Classic Interface
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| TashTwenty: Single-Chip DCD (Hard Disk 20) Interface | |
| Posted by: NJRoadfan on 2022-03-16 13:25:28 The interface is simply called "ST-506". The HD20 had a DCD to ST-506 controller in it. Reading the BMOW blog, someone mentioned a device that plugs into the floppy port and allows PC style floppy drives to be connected to the Mac. “The Kennect Rapport is a small dongle like device that attaches to the floppy drive port of an early Mac (like Plus, SE, SE/30). Easily recognizable by the small size, the port underneath and blue screw knobs. The Kennect Rapport by itself and attached to a 800K floppy drive can read/write/init 720K PC disks, as well as an advanced 1.2 MB format.” “When used in conjunction with the Kennect 2.4 Drive it adds HD read/write/init capabilities to any Mac (including Plus/SE) as well as access to HD PC disks. It can also format HD to 2.4 MB in size. Probably the best thing is to be able to read HD disks on a non-HD Mac.” Mac GUI :: Here's the dope on Kennect Technology and Rapport (LONG)Apple news, photo galleries, downloads, and discussion forums.
macgui.com
There is one on ebay for a sky high price if interested in what it looks like. It might actually be a DCD spec device that supports removable storage. | |
Posted by: cheesestraws on 2022-03-16 13:34:07Reading the BMOW blog, someone mentioned a device that plugs into the floppy port and allows PC style floppy drives to be connected to the Mac. Wow, I didn't even know that existed. What an interesting thingy. | |
| Posted by: olePigeon on 2022-03-16 13:51:24 I think you would have to have the matching Kennect floppy drive, because it's a standard Apple floppy connector port. | |
Posted by: Tashtari on 2022-03-16 22:39:05It might actually be a DCD spec device that supports removable storage.It's nice to think so, but the article mentions dropping a cdev in the System Folder, which makes me think not... | |
| Posted by: demik on 2022-03-17 10:38:37 Quick preview. It works ! It's designed as a "period correct" THT design, so people who don't like soldering SMT component can build it. It's a 2 part design. There is an activity LED which changed from yellow (reads) to bright amber (writes) (something technical not easily fixable without adding components)  It's Open Source and will be available on Github soon. | |
| Posted by: mg.man on 2022-03-17 10:46:11 Awesome! Eagerly awaiting full release - I could use a few! Now all you need is to twist @PotatoFi's arm into making a custom case for them... A la his RaSCSI case... 😎  | |
Posted by: Scott Squires on 2022-03-17 10:46:52you can order them from IEC, which has the world's worst online store (I just ended up calling them). Their store seems completely average to me. Didn't have any issue ordering. Maybe they fixed it since you ordered. | |
Posted by: Tashtari on 2022-03-17 11:18:22will be available on Github soonAnd soon is now: https://github.com/lampmerchant/tashtwenty/tree/main/pcb/TashTwenty Tiny Maybe they fixed it since you orderedMaybe! I should get some more "DB"-19s to have on hand... | |
Posted by: CC_333 on 2022-03-17 13:07:38Now all you need is to twist @PotatoFi's arm into making a custom case for them... A la his RaSCSI case...I doubt that'll be hard, as he seems to enjoy doing it. c | |
Posted by: demik on 2022-03-17 16:09:17Awesome! Eagerly awaiting full release - I could use a few! @PotatoFi cases are indeed awesome As a basic protection, the board was designed to be compatible with a case that I'm using on some projects (ex: Quack). It's available in black/light gray/translucent blue It's missing panels, they will came later down the road  | |
| Posted by: Tashtari on 2022-03-17 16:52:19 Speaking of "it works!" news, I just got my Classic II back from recap-ville today and so, for the first time, was able to try TashTwenty in a machine with a faster-than-8-MHz processor, and... it works! The downside is that it only recognizes the first drive, which is a little disappointing. It's possible that this is due to Phase3 being pulsed too quickly for the chip to recognize and react to (why would that be a problem and yet everything else be okay?), but it's also possible that support for more than one HD20 had been removed from the Classic II's ROM. I'd bet that as far as support was concerned, multiple HD20s wasn't a situation they encountered very often at all. All in all, I call it a win. It's been a good day for TashTwenty as a project. | |
Posted by: Tashtari on 2022-03-17 17:06:49it only recognizes the first driveActually, now that I think about it, this might also have something to do with the machine running System 7. In addition to only the first drive appearing, it appears in file dialog boxes with a floppy disk icon. Curious. I thought I'd read somewhere that System 7 doesn't support HD20 at all, but evidently it supports it at least a little... | |
| Posted by: Tashtari on 2022-03-19 09:42:56 Update: After that first time, I haven't been able to get TashTwenty to show up on the Classic II. I have a feeling I know why, and I have a feeling it's because the PIC's pretend-to-be-a-CPLD trick doesn't work consistently on faster machines - there's a detection step on startup that depends heavily on speed of response, and if the PIC manages to respond fast enough, great, if it doesn't you're out of luck. It still works consistently on machines in the 8 MHz club. I'm a touch disappointed, but ultimately I think I'm okay with this. 8 MHz machines are pretty much where you'd want to use TashTwenty anyway. | |
| Posted by: warmech on 2022-03-19 11:58:29 Oh my god - I have a dead HD20 that I can finally resurrect. The Rodime in it is dead, but the rest of the unit works fine. Thanks so much for making this available! | |
Posted by: Tashtari on 2022-03-19 21:32:05I have a dead HD20 that I can finally resurrect.Oh, are you going to do the thing where you use the case and install a TashTwenty board into it? If so, I want pictures. =D | |
| Posted by: mdeverhart on 2022-03-20 09:08:39 Is there a list somewhere of machines that have HD20 support in their ROMs (or otherwise support the HD20)? | |
Posted by: Tashtari on 2022-03-20 09:16:27Is there a list somewhere of machines that have HD20 support in their ROMs (or otherwise support the HD20)?There's a list on BMOW's website. Of those, the ones with both HD20 support and 68000 processors running at 8 MHz (and thus compatible with TashTwenty) are:
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Posted by: warmech on 2022-03-20 09:21:34Oh, are you going to do the thing where you use the case and install a TashTwenty board into it? If so, I want pictures. =DYep - I'll probably leave the Rodime in it for weight, but the internal floppy drive connector will just connect straight into the TashTwenty. I think there's even just enough room for it to fit next to the logic board with no modifications and still be within reach of the cable. Is there a list somewhere of machines that have HD20 support in their ROMs (or otherwise support the HD20)?Not really a [helpful] official list anywhere - Apple basically said "this is for use with the 512K and Plus and that's it." However, in reality, it will work on anything (128K aside) with a pre-Mac II ROM. The above-referenced BMOW list is all the machines that ran with such a ROM (Classic II aside, which is apparently compatible, according to MacGUI). The BMOW SE/30 replacement ROM adds HD20 support back, though, so if you have one of those, your SE/30, or Mac II-series (though not the original Mac II) machines can technically support it as well. | |
Posted by: Tashtari on 2022-03-20 09:29:06Classic II aside, which is apparently compatibleIt worked for me on my Classic II... once. And when it did, it was completely reliable, it's just the detection step that seems unreliable. There is an outside chance I'm wrong about the speed issue, but I don't think I am. All the same, if someone builds one and tries it on a different 68030 machine successfully, please do share. | |
| Posted by: mdeverhart on 2022-03-20 10:50:04 @tashtari @warmech Thanks! I’m wondering if any of the PowerBook ROMs include support, which could be nifty especially for Duos since they have an external floppy port. TattleTech lists two .Sony drivers on my Duo 230, one of which has a Type of “XL Hard Disk”, and one that has a Type of “Floppy Disk/HD20”. They’re both located in ROM at the same address, for whatever that’s worth. Anyway, I may build one of these for my SE; if I do, I may also see what it would take to build an adapter cable for the dock’s external floppy connector. Probably not a project I’ll get to anytime soon, but I’ll post an update if I do. | |
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