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ChildOfCv

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About ChildOfCv

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  1. That's an interesting potential solution, and theoretically it should work, since analog states shouldn't pull any extra power from the multiplexer. Might be fun to try. Heck, it may even work better than the digital solution.
  2. The static is gone, from what I could see. Even removing the debounce capacitors to improve response time, it was still quiet except for an occasional tiny white dot on maybe 50 joystick/button presses. Okay, so option 1 is the inverting buffer to inverting data selector: 74hc14: https://www.mouser.com/ProductDetail/Texas-Instruments/SN74HC14N?qs=sGAEpiMZZMuyBeSSR239Ias%2B1yN%2FIiBNq5xI0bbHe7g%3D 74ls158: https://www.mouser.com/ProductDetail/Texas-Instruments/SN74LS158N?qs=sGAEpiMZZMtxONTBFIcRfk9GpaUoLd0cKrV198MuqdA%3D Another option is the non-inverting buffer to non-inverting data selector. You'd have your choice of NOT gate plus 4019, or a 74ls157. 74AHC8541 is also a usable choice. Actually, you can set it for inverting or not, so it could be made to work with either data selector. *74AHCV17 https://www.mouser.com/ProductDetail/Texas-Instruments/SN74AHC8541N?qs=%2Fha2pyFaduildg0HBe%2FQufJuLq6%2FoFr3geyhxP%2Fr1Co%3D (but also needs https://www.mouser.com/ProductDetail/Aries-Electronics/LCQT-TSSOP14?qs=%2Fha2pyFaduh3s%2F01dvn%2Fga6dGKUFOQKWguYfMiqGSvvV40Tsjgf1HA%3D%3D for use with a breadboard) 74AHC8541 https://www.mouser.com/ProductDetail/Texas-Instruments/SN74AHC8541N?qs=%2Fha2pyFaduildg0HBe%2FQufJuLq6%2FoFr3geyhxP%2Fr1Co%3D 74ls157: https://www.mouser.com/ProductDetail/Texas-Instruments/SN74LS157N?qs=sGAEpiMZZMtxONTBFIcRfpKvrGTByBdiIFx8m8XZjlw%3D *CD4019B https://www.mouser.com/ProductDetail/Texas-Instruments/CD4019BE?qs=sGAEpiMZZMtMa9lbYwD6ZHl%2Bb36l%2BC4RxjVZZsInI%2BQ%3D and 2N3904 I marked the ones I actually used with an * 1M potentiometer (good enough to dial in a response time) https://www.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P160KN-0QD15B1MEG?qs=sGAEpiMZZMtC25l1F4XBU7XpbFdDDzhr3l49V2gsqx8%3D When I looked at the 2600 trackball schematic again (the one that's part of the 7800 trackball schematic) I noticed that the less-official schematic is off by an order of magnitude on the inductor. So here's a 150uH one that matches what the 2600 uses: https://www.mouser.com/ProductDetail/Bourns/78F151J-RC?qs=sGAEpiMZZMsg%2By3WlYCkU0AkrlqHXBx5xpBcD11zi1c%3D Finally, with the trip point of the schmitt triggers at around 3V, it may be useful to reduce the line voltage to the joysticks by a bit. So instead of a single 1M pull-up, maybe it needs a 330K pull-up and 680K pull-down. Something like this:
  3. Here's a fixed version. Biggest fix is line 250 which used the same variable name twice in the declaration. Also fixed a number in the solution data, the cheerleader message data, and the use of { where ( should have been used. PEGJUMP.BAS
  4. So, for those with working SECAM units, what channel does it broadcast on? 3? I've heard that there are some versions that broadcast on UHF, but the final output modulator on this rev 7 board is only good for low VHF range, according to its datasheet. I'm asking because my multisystem TV uses a fine-grain tuner that can tune in even when the signal is not on a proper frequency, so that gives me two degrees of freedom. But the output filter on the RF is likely tuned for one specific channel and is supposed to remove noise in that range, so if you're not at least in the ballpark you'll probably never get a good output signal. And to complicate matters even more, I had to replace the tuning coil since its ferrite slug was disintegrating, and I don't know the intended range, so I just bought a few different ones. Had to replace the processor socket since an address line wasn't making good contact, and now it at least runs larger cartridges. But even B/W mode shows a lot of interference, and sound effects completely screw up the screen.
  5. The original power supply only outputs its correct voltage under load, or so I'm told. Either way, the first stop inside the console is a voltage regulator, which has an absolute maximum input voltage of 35V. Probably less with the tiny heat sink that they mount it to, but definitely more than 14.8V.
  6. This setup seems to be the most successful so far. It's two 74AHCV17's (non-inverting hex buffer with schmitt trigger inputs) and two CD4019B's (quad data selectors). You might be able to make something work using the chips you've already acquired, but the point is that 1) it's a schmitt trigger input with resistor pullups and capacitor debounce. 2) There is no output contention. The 4019B's use OR gates to combine the separate inputs, so there isn't a problem even when both are activated. Since I only needed one NOT gate, I just used a 2N3904 transistor and a few resistors to make it. Why waste an entire chip for one gate? The capacitor values are just a guess. I used 0.1uF, but they hold active for a noticeable time before returning, so that's not good for action games. So I cut it by 10x in the schematic. A good approach might be to use the 0.1uF capacitor with a 1M potentiometer, then keep adjusting the potentiometer until the response looks good to you. Then the values can be normalized through chosen resistor and capacitor values. Alternative ICs would be 74ls14 for the buffers and 74ls158 for the multiplexer. The 158 has the additional benefit of not needing the transistor. temp.pdf
  7. The error at 1020 is overflow. Apparently you asked for a 40 second pause. The most that will work with an integer loop is 32.
  8. On line 240: "QUIZ-NAKE" On line 370: LOCATE 5.1 <-- should be LOCATE 5,1 On line 500: Missing closing parenthesis On line 560: ANSWERES On line 1180,1190: There is something else wrong between 1180 and 1190. 1180 is probably missing a LOCATE. But really, it's bad even as designed. Better: 1180 IF K$ <> CHR$(8) THEN 1200 ELSE IF LEN(A$) = 0 THEN 1150 1190 XP=XP-1:IF XP<1 THEN XP=40:YP=YP-1 1195 A$=LEFT$(A$,LEN(A$)-1):LOCATE YP,XP:PRINT " ";:GOTO 1150 1330 "SCRE:" <- "SCRN:" Also, this would have been an excellent use of the RANDOM access type for files.
  9. One thing that can really kill your zapper's range is if the lens on the front falls out.
  10. There is a solution that replaces the 8 chips with a different 8 chips that require only one voltage, but nobody has attempted to replace them with a single chip. It could be useful though, as even those newer chips are probably in the discontinued state by now. I guess your single-chip solution uses x8 DRAMs instead of x1?
  11. From what I saw of the original solution, the creator was a tinkerer and not an engineer, and just knew op-amps and followed the cookbook. A better solution is always welcome The biggest gotcha with the signals is that the B-Y pin sends out a negative pulse during the color burst period, and many TVs (and presumably YCbCr input processors) take that same time to synchronize on the blue level. So for component output, at least, you have to suppress that or you get some ultra-blue images. I've seen a Hackaday project that uses a sample and hold circuit to do that.
  12. Neat. I tore apart a SNES controller port, moved a couple pins into the missing pin positions for the gun, then wired the inside into a NES light zapper. The only issue at first is that pointing the gun at a light pulled the trigger and vice versa. A quick pin swap fixed that though. But it's also nice to see a solution that doesn't involve breaking a SNES connector.
  13. I'm suggesting that the possibility that they don't even delay the color burst. Let the TV interpret it however it will, but we always pretend we're sending the same phase. For a PAL TV, the actual colors displayed would depend on mixing two different interpretations of the same relative phase. Perhaps averaging between two cells causes duplicate colors. So maybe removing 3 registers redistributes the color wheel in a way that has fewer duplicates. I'd like to see the PAL schematic, but I have yet to locate one either. Maybe they will be discovered eventually on one of the Atari tapes.
  14. The delay pot is connected to the gate of a transistor on every cell of the shift register. It definitely determines the speed of propagation throughout the entire register. And you need that anyway. NTSC has a 3.58MHz modulator. PAL has a 4.43MHz modulator. So you need them to have different propagation rates in order to make the square wave complete across the number of color cells. But each cell should represent an equal portion of 360 degrees regardless of standard. Remember that during the blanking period, the square wave is fed out directly through the color output (the color burst). The other colors are phase-compared with the burst signal to determine the actual color. On NTSC, the burst is 90 degrees and represents negative blue (yellow). On PAL the burst is 45 degrees on one line and 135 on the other. My hypothesis is that it does not bother flipping a bit to change the actual phase, but instead accepts that you'll be combining two colors because you're outputting from the same register on each line, and on alternating lines the same register means something different. You noticed that you lose a color or two in that setup, and indeed the PAL palette is smaller than the NTSC palette. So that actually seems to confirm my suspicion. You'll also notice that the PAL palette has an unnatural progression, which fits your observations. That also seems to confirm my suspicion.
  15. Actually, the solution is even easier than that: White and black output no color component at all. This is because the phase control is for differences from white, one in the red-green direction and another in the blue-yellow direction. If you look at the color wheel, you'll notice no white or black. That's at the center. White is full saturation with no color shift, and black is no saturation. So when it's a shade of gray, the difference in both directions is zero. On the internal schematic for the TIA, white and black are not connected to the color output.
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