+Ksarul Posted October 1, 2016 Share Posted October 1, 2016 For those who've been wondering what I've been up to lately, I've been working on something interesting for Richard Bell. I received a couple of test boards for the project today, so I had to start building one right away--even though I am still missing a few of the important parts. At least it is beginning to look like a piece of TI hardware. . .and just because I know there will be people asking this: there is absolutely NO timeline on when this will be finished or made available yet. I know there are some bugs on this iteration of the board before I even build one--and I may find more as I try to test it. More importantly, I still have to get a good dump of the PAL for the original Myarc board so that I can make new ones--as otherwise, that particular portion of the project will become a really fun bit of whack-a-mole. . . 8 Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted October 1, 2016 Share Posted October 1, 2016 For those who've been wondering what I've been up to lately, I've been working on something interesting for Richard Bell. I received a couple of test boards for the project today, so I had to start building one right away--even though I am still missing a few of the important parts. At least it is beginning to look like a piece of TI hardware. . .and just because I know there will be people asking this: there is absolutely NO timeline on when this will be finished or made available yet. I know there are some bugs on this iteration of the board before I even build one--and I may find more as I try to test it. More importantly, I still have to get a good dump of the PAL for the original Myarc board so that I can make new ones--as otherwise, that particular portion of the project will become a really fun bit of whack-a-mole. . . I have two or three "variants" of the Myarc FDC if anything from those boards will assist in the endeavor. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 1, 2016 Author Share Posted October 1, 2016 (edited) If you look carefully at the picture, you will see that quite a few of the random discrete components are very different from the boards Myarc made. This one incorporates a series of stability-enhancing modifications from Michael Becker. According to Richard, this was the most stable Myarc FDC card he'd ever seen, which is why we decided to base the new layout on it. All of the additional components are propely integrated with the board in the places Michael inserted them into the design. All of the superfluous extra bits and references have been removed. I also marked the positive leads for all of the capacitors so that all of them can be Tantalum caps--but most of them can be left as axial ceramic caps with no ill effects. And for those who really like their boards to be in clamshells, The two gold tabs can be carefullly removed with a saw, cutters or a file. Once they're gone, the card has all of the necessary holes to insert it into an original clamshell without shorting something out. . . Edited October 1, 2016 by Ksarul 3 Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted October 1, 2016 Share Posted October 1, 2016 What FDC chip are you using for this? DSDD, I assume? Any reason, aside from the valid reason of lacking a DSR, to not go with an HD-capable (1.44MB) FDC? Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 1, 2016 Author Share Posted October 1, 2016 I am using the same chip as Myarc did in most of their cards, a WD1770. That gives us up to four 720K drives. . .and it has an existing DSR. Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted October 1, 2016 Share Posted October 1, 2016 The photo is a bit small to see all the detail. I assumed it incorporated changes Richard showed us at a fair years ago. My cards were modified with AMA/B/C and some stability updates that are probably moot with Michael's changes. I did have one card with a WD1772 that we were playing with to enable high density support, but like the Myarc HFDC, the DSR would need to be updated. Paolo B. had documented much of the DSR memory layout but there are no known copies of the commented source code available to inspect or modify. I assume you'll stick with the most stable 720K DSR. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 1, 2016 Author Share Posted October 1, 2016 The AMA/B/C mods might be very useful when using it with a Geneve or with a 99/8. . .on the DSR, I will have to look through the last of the disks I inherited from Mack McCormick when he sold his systems in Germany (many years ago). I think there may have been source code for one of the controllers that existed back then (FDC or SASI HD) on one of the disks. . .but it has been a long time since I looked at those disks. 2 Quote Link to comment Share on other sites More sharing options...
Omega-TI Posted October 1, 2016 Share Posted October 1, 2016 The photo is a bit small to see all the detail... I blew it up a little and enhanced his image a tad, because like you, I wanted to see some detail. Hopefully we get another image down the road a bit. ( CLICK ON IMAGE TO ENLARGE OR SAVE ) 2 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 1, 2016 Author Share Posted October 1, 2016 I have really nice blown up images of this card. I actually reduced the size of my original picture by about 80% to put it up here (to keep from bogging down browsers). I can put up a more detailed one tomorrow. . .now I just need to wait on some 470-Ohm, 1% resistors. . .I may have some in my mix of metal film stuff that I bought a few months ago though, which would give me enough to do some testing. Quote Link to comment Share on other sites More sharing options...
Shift838 Posted October 1, 2016 Share Posted October 1, 2016 that's one pretty card. I know alot of us will be all over it once it's released. And it will be well worth the wait! Quote Link to comment Share on other sites More sharing options...
+InsaneMultitasker Posted October 1, 2016 Share Posted October 1, 2016 The AMA/B/C mods might be very useful when using it with a Geneve or with a 99/8. . .on the DSR, I will have to look through the last of the disks I inherited from Mack McCormick when he sold his systems in Germany (many years ago). I think there may have been source code for one of the controllers that existed back then (FDC or SASI HD) on one of the disks. . .but it has been a long time since I looked at those disks. The AMA/B/C hardware mod is documented in the Genmod guide and is relatively simple, requiring only one chip and some connections to address lines, if memory serves correctly. 2 Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 1, 2016 Author Share Posted October 1, 2016 I knew I'd seen that circuit somewhere! Thanks for the timely reminder, o InsaneOne! For the folks that wanted a more detailed picture, here's the original. 6 Quote Link to comment Share on other sites More sharing options...
+Schmitzi Posted October 2, 2016 Share Posted October 2, 2016 great news thanks Quote Link to comment Share on other sites More sharing options...
aftyde Posted October 3, 2016 Share Posted October 3, 2016 Any chance the card will fit into a TI clamshell? That might be a good thing. That's awesome - the Myarc DDCC is the only card I have that completely and perfectly works with the Lotharek floppy emulators. All other controllers read and write, but only the Myarc will init a .hfe disk image. If I had access to these boards - I'd chuck all the other controllers back into the history bin. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 3, 2016 Author Share Posted October 3, 2016 (edited) All you have to do to put these into a TI clamshell is to carefully cut the two gold-plated tabs off. The board has all of the holes placed in the same spots the TI board did so that you can put them into a standard clamshell without problems. We're also still working on getting a good copy of the JEDEC files for the GAL. The only copy we have of the modified GAL used on this version of the board apparently has the fuses blown, so we can't read it. Next step is to track down the documentation we have on it (we think we have a description of the equations, but Richard is still looking for that document). Until then, we can test the board layout to verify that everything is right--but we won't be able to produce them for others until that problem is resolved. Edited October 3, 2016 by Ksarul Quote Link to comment Share on other sites More sharing options...
+mizapf Posted October 3, 2016 Share Posted October 3, 2016 I am planning to write an emulation for the DDCC-1 for MAME; I already created ROM dumps and some photographs of the PCB, but with circuits still in place. Are the PCBs shown above equal to the original DDCC-1 PCBs? Do you have the original GAL definitions? Quote Link to comment Share on other sites More sharing options...
RickyDean Posted October 3, 2016 Share Posted October 3, 2016 All you have to do to put these into a TI clamshell is to carefully cut the two gold-plated tabs off. The board has all of the holes placed in the same spots the TI board did so that you can put them into a standard clamshell without problems. We're also still working on getting a good copy of the JEDEC files for the GAL. The only copy we have of the modified GAL used on this version of the board apparently has the fuses blown, so we can't read it. Next step is to track down the documentation we have on it (we think we have a description of the equations, but Richard is still looking for that document). Until then, we can test the board layout to verify that everything is right--but we won't be able to produce them for others until that problem is resolved. There is supposedly a process that lets you remove the outside of a chip via a dissolving medium and then you can see the logic inside and decipher the circuits. Would that work with these Gal's and Pal's? Quote Link to comment Share on other sites More sharing options...
Tursi Posted October 3, 2016 Share Posted October 3, 2016 There is supposedly a process that lets you remove the outside of a chip via a dissolving medium and then you can see the logic inside and decipher the circuits. Would that work with these Gal's and Pal's? Not normally... the process is done visually, and seeing the programming of a programmable logic ranges from difficult (if it blows physical fuses) to impossible (if it's just storing charge). It's theoretically possible to probe and read a decapped device, but insanely difficult... I can't think that I've heard of any successes beyond a couple of bits. For something like this, understanding the circuit and software and recreating the logic would be easier. Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 3, 2016 Author Share Posted October 3, 2016 The PCB has a number of modifications done to it, Michael. They incorporate the rats-nest of changes done to the regular boards to produce the most stable version of the board ever fielded (Michael Becker made the mods). About 90% of the traces are the same as the original. I have one original board that I removed most of the components from, so I could take a picture of that for you if you like. . . 1 Quote Link to comment Share on other sites More sharing options...
RickyDean Posted October 3, 2016 Share Posted October 3, 2016 I want one when their ready But I am still going to try to do some of my own work trying to get ti cards to do double density with the controller chip being changed. 1 Quote Link to comment Share on other sites More sharing options...
+mizapf Posted October 3, 2016 Share Posted October 3, 2016 The PCB has a number of modifications done to it, Michael. They incorporate the rats-nest of changes done to the regular boards to produce the most stable version of the board ever fielded (Michael Becker made the mods). About 90% of the traces are the same as the original. I have one original board that I removed most of the components from, so I could take a picture of that for you if you like. . . Without sockets? That would indeed be great. The PAL is a 12L6, so not a registered one, and I guess it only decodes the ROM, its page, and the devices. Quote Link to comment Share on other sites More sharing options...
Stuart Posted October 3, 2016 Share Posted October 3, 2016 Ksarul, on 03 Oct 2016 - 1:23 PM, said:We're also still working on getting a good copy of the JEDEC files for the GAL. The only copy we have of the modified GAL used on this version of the board apparently has the fuses blown, so we can't read it. Next step is to track down the documentation we have on it (we think we have a description of the equations, but Richard is still looking for that document). Until then, we can test the board layout to verify that everything is right--but we won't be able to produce them for others until that problem is resolved. If you can't find the equations ... as you presumably have a circuit schematic you know what signals are connected to the PAL/GAL inputs and outputs. Should be fairly straightforward to knock up an adaptor to exercise the inputs and see how the outputs respond, and reverse engineer the equations from that. Quote Link to comment Share on other sites More sharing options...
+jedimatt42 Posted October 4, 2016 Share Posted October 4, 2016 If you can't find the equations ... as you presumably have a circuit schematic you know what signals are connected to the PAL/GAL inputs and outputs. Should be fairly straightforward to knock up an adaptor to exercise the inputs and see how the outputs respond, and reverse engineer the equations from that. I'm surprised this isn't something that is automated with the universal programmers that are so prevalent today... -M@ Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted October 4, 2016 Author Share Posted October 4, 2016 I don't have a schematic for the card yet--although I eventually plan to build one based on the card layout, now that I have that part done. 1 Quote Link to comment Share on other sites More sharing options...
aftyde Posted November 15, 2016 Share Posted November 15, 2016 For those who've been wondering what I've been up to lately, I've been working on something interesting for Richard Bell. I received a couple of test boards for the project today, so I had to start building one right away--even though I am still missing a few of the important parts. At least it is beginning to look like a piece of TI hardware. . .and just because I know there will be people asking this: there is absolutely NO timeline on when this will be finished or made available yet. I know there are some bugs on this iteration of the board before I even build one--and I may find more as I try to test it. More importantly, I still have to get a good dump of the PAL for the original Myarc board so that I can make new ones--as otherwise, that particular portion of the project will become a really fun bit of whack-a-mole. . . Is there a schematic of this card? Or a picture of the reverse side I could look at? Quote Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.