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Falonn

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About Falonn

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  1. Back in 2014 (as a kind of capstone project during a year where I focused on self-learning electronics), I made a little DB9-to-USB adapter for Colecovision controllers. The new idea was the inclusion of two ports so you could connect a Roller Controller. There is a little switch to make it behave like a standard mouse so you can use it in emulators that have Roller Controller support... or just use it as a trackball in Windows or whatever because it's fun. The video mostly focuses on the electronics, but it does show the thing in action near the end: This was also before I knew anything about designing for 3D printing, so the case isn't great. It mostly does the job, but that unintended sliding action is the part of the project that I'm still the least happy with. I didn't know about this community back then, so I never really shared it with anyone. Now that I do know about this place, I finally get to share it six years later. All the files are on GitHub if anyone wants to try making one. The PCB includes an ISP header, so it should be easy to program the microcontroller with one of those $7 USBasp thingies from Amazon.
  2. I don't have any advice, but I'd be interested to hear the answer, too. The quadrature scheme used by each axis should prevent anything like static or noise from causing problems like that. How strange. That's amazing that it's so repeatable! I've never seen this with my CV + Roller Controller + Slither combination. How much force is required on the ball to prevent the motion? Is it only the slightest touch from a finger tip (like a touch-sensitive lamp)? That would indicate some electrical fishiness. Otherwise, if it takes more force, that would point to something mechanical. Do you have both controllers plugged into the Roller Controller's pass-through ports, or only one?
  3. I can vouch for the French PCBs from eBay. They go up to 32KB and are super easy to use: just bridge the correct jumper and solder in a socket. At quantities of 4 or more they're nearly half the big listed price there, too.
  4. Nice work. That output looks great. Can you confirm whether the audio still works on the machine? I haven't been following the thread closely, but last I saw, the audio subsystem relied on a clock output from the '9918A that isn't there on the '9928A.
  5. For what it's worth, I saw this all through development, too. The Framemeister is razor sharp with zero noise. I always saw faint jailbars through the OSSC when against a black background. But making the offset changes in step #10 of the install guide cleaned it up. All that's left on the OSSC afterward is a very tiny bit of overshoot in rare cases. (The Framemeister is also able to clean that up somehow, too, leaving emulator-like, essentially perfect output.)
  6. Interesting, the hand-drawn version mentions a TMS9318A for the VDP with a hastily corrected "9929A" written above it. Maybe they were planning to use some future VDP product that never materialized? And designing it for both styles of output explains why all the jumpers are there for choosing between composite and component'ish output. It also looks like the hand-drawn schematic must have been the source of the SGCCK vs. SGC CLK naming discrepancy on either side of W104. The same names are used on the same pages in the same places as the other PDF.
  7. That's the same link I included 25 posts ago, back on page 3! Though, like ChildOfCv noticed, be careful scrolling through it too fast: it contains two sets of schematics, one for the 99/4A and another for the 99/4QI... whatever that is. Yeah, like Ikrananka was saying, this would be a roundabout, inefficient path. The output signal is almost natively component. So you'd be going component'ish --> RGB --> component, where at least that first step (through the LMH1251) sucks up a lot of power. A component-only board would only require half the parts, half the power, potentially half the PCB size (or possibly double the component size to make it easier to solder by hand?), and less than half the cost because it wouldn't need the expensive LMH1251 anymore. I'm not sure how useful a component version would be to the wider community, seeing as most new TVs are dropping component inputs completely. But, after that laundry list of benefits above and knowing that it's just TMS-RGB with a few things removed, I'm interested now just out of completeness.
  8. The links are a little buried on the tms-rgb.com site, sorry. On the BOM page, there are a pair of "this breakout board" links that take you to the relevant OSHPark project pages for the 8-pin and 9-pin breakouts.
  9. Oh, I hadn't even gotten that far in the document. Interesting. I also just spotted the footnote on page 23 that confirms my hypothesis: "SN76489 uses 3.58 MHz clock supplied thru W104 coax". So the TI-99/4A's sound chip definitely uses the VDP's clock out signal.
  10. There are two pin 38's coming out of the chip. On the left side, pin 38 goes to the SGCCK signal (through grounded shield W104). On page 23, there is an "SGC CLK" at the far right that also passes through a grounded shield named W104, so I'm guessing they just changed signal names (accidentally?) between pages. (All of these 1980's TI datasheet are riddled with errors, so it wouldn't surprise me.) From there it appears to go to the audio chip and (through another jumper) to some "GROM" stuff.
  11. No, not at all. I was able to find a 99/4A schematic though (on page 20 of this PDF) and it looks promising that you might not have to modify the board beyond adding/removing a couple jumpers. It looks like it might have been designed flexibly to accept either VDP. The J201 header is even labeled with B-Y and R-Y. The main trouble I see is that the CPUCLK output line (which isn't a clock at all on the 9928A) appears to actually be used somewhere else on the board for something. It might be worth trying to find an account from someone that has already done the 9918-->9928 conversion (with instructions for changing the jumpers) before trying to RGB mod it.
  12. I tried my best to find a list of systems that use the 9928A, but there is a lot of unreliable/conflicting information out there! I've already had to amend that list once. Does this mean I got the SG-1000 wrong, too, and that it should be removed from the list? For composite (or RF) out, you'd need an extra one, but just for the VDP's general operation, I think the datasheet shows that they both use the same 10.738635 MHz clock. The only differences I see between the two are on three pins: pin 35: EXTVDP on the 9918A / B-Y on the 9928A. pin 36: composite video output COMVID on the 9918A / Y on the 9928A. pin 38: the "typically not used" CPUCLK on the 9918A / R-Y on the 9928A. It would be easy to just leave those three 9928A pins disconnected from the rest of the original circuit board by leaving them bent up or by cutting a trace on the board or something like that, except there is one key requirement laid out in the datasheet: they require a small "load circuit". For pin 36, this should already be present, because it's required for both chips: For pin 35 and 38... who knows what circuitry is already there. But there needs to be a resistor to ground on each: If there is much else going to/from those pins, I'd worry that whatever the TI-99 board has in place for EXTVDP and CPUCLK, it might be causing the trouble you're seeing on your TV screen there.
  13. How curious! Was this a board from Mobius or did you build it from scratch? The first thing to double-check is that the resistors in this section of the board all have the values they're supposed to: If any of them got swapped around, it could cause different level colors like that.
  14. List updated. (You'll need to hard-refresh if you've looked at it in the last 24 hours.) Otherwise, please give your offshoot project a different name to avoid confusion. "v3" would mean something specific for this GitHub repo's release list. Maybe TMS-Pix instead?
  15. For what it's worth, I don't ever expect to sell any myself. The list to keep an eye on is the "People offering pre-assembled TMS-RGB kits" on this page. (And for anyone interested in making/selling them, just let me know and I'm happy to add you to that list.) ... or just send your system to Ruggers Customs and he'll install one for you. (There's a list for that too, but he's the only one on it.)
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