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MrPix

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Everything posted by MrPix

  1. MrPix
    I’ll look at this tomorrow and see if it will speed things up. Any additional info helps as the datasheet is a bit lean. The logic is straightforward, but the way the outputs are used to generate NTSC is, to be kind, obtuse. I understand it after other projects, but still, recreating it in a color system like RGB that has a smaller color gamut, never an ideal situation. I’ll do the best I can and most people will hopefully be happy. So many shades of green!
  2. MrPix
    Aaaand I think I just got a loaner machine organized, so when that arrives things will go a lot more quickly. Sweet!
  3. MrPix
    Luckily, where I have decided to intervene in the video generation in the easiest spot, in terms of desoldering the smallest IC possible and simplest access to the needed signals. I'm not touching any super hard to find ICs, and not asking people to desolder 40 pin ICs where there's a better than even chance they'll trash their console. Why does the Inty get no love? I looked around and there's hardly anything for it.
  4. MrPix
    Best. Edit. Reason. Ever. Yeah, you might be Woz, but I'm not ordering your design until you send me video, in triplicate, of that exact PCB design working. Also, I'm assembling a pick and place machine right now. It might take a few weeks to get the whole thing together, but when it is, it will save me a LOT of time assembling these boards. I plan to panelize them in 2x10 or 2x20 so I can mount parts on 20 or 40 in a go. 2x20 will just fit in my reflow oven.
  5. MrPix
    I looked at it but it has its tentacles into everything and is an order of magnitude more complex than I want to tackle right now. I just imagine people would be grateful for a simple and easy to install RGB solution. Tackling the STIC would push me out of small CPLD territory into FPGA territory and working out some quite complex logic interactions based on hidden internal registers. Which, eww, by the way.
  6. MrPix
    I did a little work on this, over the last week. As I don't own or have access to an Inty in person, I have been working backwards, while keeping an eye on the auctions for a basically functional unit to snag. So, the video output section has been done, and I plan to build it with the R2R ladders for the analog RGB output, based on fake input to the logic block. After that, hooking up the input logic to the output logic is simply a case of making a truth table of which output color relates to which input color. I have a few spare pins, so I will be able to have a jumper for selecting PAL/NTSC palettes. When I get that all together, I'll post some captures of the colors and get some feedback.
  7. MrPix
    The first of the components I ordered has arrived. I'm waiting on @Falonn to fully test out the current board revision and give me a nod before ordering the 250 PCBs and solder mask. It's been quiet for a while - just thought it would be good to remind everyone that things are progressing forward - slowly
  8. MrPix
    No, it doesn't alter anything on the board.
  9. MrPix
    That is the previous citrus3000psi board. It has some problems that our board fixes.
  10. MrPix
    Google ‘sarcasm’ ?
  11. MrPix
    I’m going to be making and selling them. I’m not keeping a list as there will be enough for everyone. I’ll be making a couple of years supply to keep costs down.
  12. MrPix
    I can deliver if someone hits me up with a specific need.
  13. MrPix
    Velocity? That's so last hour. We're going Symmetrical!
  14. MrPix
    That thing looks expensive!
  15. MrPix
    I would be quietly interested, yes. Depends on the smallest part. Though, PCB layout is my forte and I'd really like to layout both boards from a correct schematic soonish... and with some modest improvements to power, memory and more modern component choices. Like, 90s Want to talk about it in PM?
  16. MrPix
    Probably, but wouldn't be as much an improvement as re-fabbing the board in 4-layer
  17. MrPix
    I learned through hearsay that there are four missing HSYNC pulses before and four after the VSYNC pulse. I am trying to buy an economical Inty so I can produce some oscilloscope images and work out exactly what I need to do to regenerate those missing sync transitions. The OSSC uses a notoriously bad but cheap sync detector that cannot handle even a very temporary loss of sync, so it thinks there's not a valid signal.
  18. MrPix
    In my guidance I didn't think about voltage too much but more protection against ground bounce, which I have seen can be a problem on the three Adams I have access to. Luckily, the power fills and capacitor design on the board is quite solid. It would help to have a 10uF+ electrolytic on the top board near the ribbon cable, and a 1 to 2.2uF tant close to the VDP/DRAM. That's not in the scope for the board, though. I have been nibbling away at a replacement complete board. With modern components, I'd only be using maybe 1/4 of the PCB area available. It would be quite easy to incorporate a power supply onto the board that would run off a laptop power supply, with efficient buck regulators and -ve generated on board. That said, I don't know if the lower board would be happy being backfed power from the upper board.
  19. MrPix
    4.6V is a bit weak - below spec for the very picky LMH1251. On which note, I went through its data sheet one last time, searching for any indication on the practice of tying unused pins to ground. The datasheet gave me nothing. As it includes selector functionality for a second input, it gives no guidance on if it is helpful for those unused inputs to be tied to GND, as is traditional, or if they're internally disconnected. As we have no guidance, we need to test it. Could you pull out your breadboard example and test the effect on power consumption and heat generation of grounding pins 1 thru 5? That's H_in, V_in, R_in, G_in, B_in. Could you also look at those pins on your scope ungrounded, and see if they're floating or oscillating? If they are, they will need tying to ground and this will have positive effects for the IC. You might need to treat RGB separately from HV.
  20. MrPix
    I looked at it. To reproduce his palette requires 18 bit color data, which is really inconvenient. I mean, it's doable, but with just a little bit of massaging that gets it into 16 bits allows a lot of scope for configurability of palettes later.
  21. MrPix
    Sooo, with a better understanding of the problems ahead... I think for the initial revision I will have to walk back talk of fixing the sync problem that trips up OSSC. Not that it's a huge problem, but getting the circuit basically working and used on a few select systems to see how people do with the palette - collecting feedback, that's a priority. It does seem people are more sensitive about colors than about OSSC compatibility right on the first try. I'm also thinking of ways I might read the data into a frame buffer for upscaling and HDMI output a different way. One that's a lot cheaper than OSSC and other traditional HDMI solutions. Maybe using a Pi Zero and one of the open source bare metal framebuffer projects.
  22. MrPix
    Oh, that's problematic. I'm trying to make an OSSC compatible RGB adaptor. I need to reconstruct the sync as it has two groups of four missing pulses and they prevent the OSSC from locking - which is actually an OSSC problem - they used a not very good IC in their OSSC design that can't handle even temporary loss of sync.
  23. MrPix
    I've looked at the missing sync signals a little more. If anyone here is DEEPLY familiar with the inty ROM, could they look at the section that manages the manual handling of the V1 thru 5 generation and see if the lack of those 8 sync signals is simply a BIOS bug? Being able to include a replacement ROM image would be much simpler than building a sensitive PLL circuit. Cheaper too.
  24. MrPix
    They only made four Intellivisions. Everything after that was the result of a highly successful selective breeding program.
  25. MrPix
    How would you feel about an extended yet compatible cartridge port/expander that goes in the expansion port. I'm asking because I'm working on a new extended CV replacement mainboard that can solve a lot of these issues in a backwards compatible way.
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