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Kalvan last won the day on September 10 2021

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  1. It looks like you can either take two clock cycles to use the DMA to use the Dual-Port RAM as audio buffer, or else use the DMA or the CPU to take four cycles (at least) to use the DDR2 as sound RAM, which may be necessary if you've exceeded your total sprite, or scanline limit, and wanted to add in some BOBs as extra enemies, bullets, fireballs, or clouds in your vertical-scrolling shoot-'em-up, or bit-bang in more parallax scrolling fields? Question No. 1: While it doesn't look like it will happen in hardware, do you plan to designate specific stretches of Dual Port and/or DDR2 as sound buffer? Or will programmers have to be doubly careful about reads and writes to prevent the use of sound data as general logic code, or the YM2149s from reading data meant for A.I. routines and spitting out garbage from the speakers. Question No. 2: Do you believe you have enough fabric RAM to stick a YM2151 on the Nexys A7-100T?
  2. Oh yeah! This means that you could recreate the waterfall effects of, say, the Sonic games, but make them work with (relatively) sharp A/V Multi-Out or VGA video output. @epsilon537, if you're reading this, would this addition compromise the geometry of the softcore of the BoxLamda too much?
  3. Well, The X1-010 was used in a whole bunch of arcade games by the likes of Seta, Alumer, Visco, Athena, Tecmo, Sammy (Before the merger with Sega), Data East, and especially Banpresto. As I've seen footage of Twin Eagle: Revenge Joe's Brother running on the MISTer platform on YouTube, I'm certain that it's out there to find. Or, one can theoretically find the source code for core for the Seta 1st Generation Arcade Hardware and try to isolate the HDL code for the X1-010 that way. The Phillips SAA-1099 was used in the SAM Coupe, The Creative Labs GameBlaster and early SoundBlaster series cards, a couple of Mid-Late Eighties Digital Equipment and Silicon Graphics workstations (as a timer generator and peripheral I/O controller), and several arcade games by Century Electronics. The really tricky one would be the YM2414. It's an eight channel, four operator FM synthesizer with eight possible waveforms that was only used in Yamaha keyboards, and (second sourced) in midrange keyboards and synth modules by the likes of Moog, Budcla, Korg, and Casio. I fell in love with its sound on YouTube, but if it's not available, the YM2151 will work fine. Dumb question: How fast are you going to clock that 32-bit RISC V core? I ask this because you may need a separate Sound CPU and audio buffer, especially if you want to experiment with the joys of PCM polyphony at high sample rates without bogging down the rest of the system. I would suggest either the Hudson HuC6280 (Also used as a Sound CPU in arcade games by Taito and Data East), or the Zilog Z180, as each can address 1 MB plus of memory on their own. Another Dumb Question: Which FPGA are you planning to use, and how much I/O will you able to play with?
  4. Well, for the audio solution, I would like to suggest a combination of the Seta X1-010, X2 Phillips SAA1099, and the Yamaha YM2414. All those sound chips would have been from the '80s, there's plenty of tracker music for each of them on YouTube, and together, they cover almost all the basics (Geometry Synthesis, PCM, Wavetable, and FM Synthesis) except Mathematical Synthesis like Additive (Atari AMY) or Subtractive (Like the Roland MT and Sound Canvas families). If the YM2414 is unavailable as a softcore, I'm certain the YM2151 is definitely out there.
  5. I suspect the setup should be able to run SymbOS no problem.
  6. Well, my idea might not be retro enough, but it would basically be a DE-10 Nano FPGA Board, with a few other boards (SDRAM or QDR SRAM, various retro port headers, possibly an onboard scan multiplier with options for letterboxing, as the monitor resolution is 2256x1504) attached via ribbon cables, stuffed into a Framework laptop chassis, with a whole bunch of interface cards (and dongles, for ports and jacks too wide to fit onto a Framework interface card). That way, the computer can be as retro as you're willing to make the FPGA softcore for it, or you can look to the MISTer FPGA project to ask yourself what if a specific company could (and did) develop a fully software compatible laptop version of the machine of your youth. But that's just my idea. YMMV.
  7. It would depend on how many FPGA resources were left over, and whether or not the MMU would fit in the FPGA geometrically...
  8. This is in reference to the thread here. Personally, while I have several concepts for projects involving the FPGA core, I'd say that I would first like propose possible ideas for alterations and improvements to the core before its reimplementation in new projects: 1: The removal of the sound channels, and the reimplementation of the audio buffer as more video RAM. That way, if the system has its own sound CPU, there won't be timing issues between it and VERA. 2: Changes to the resolution and aspect ratio, to mimic classic arcade, console, or computer resolutions, multiples thereof, or allow for more even addressing math for Video RAM. 3: The use of larger FPGAs with more SRAM in the fabric, to allow for more Video RAM, and more graphical features, such as more sprites, more frames per sprite, affine/scaling and rotation for sprites, a wider master palette, more and/or bigger CLUTs, wider bitmap modes with scrolling registers, some sort of blitter function, more scrolling fields, and/or the elimination scanline limits for sprites. 4: A larger memory bus and/or a separate external memory interface, both to allow more video RAM than the fabric can provide, and to allow separate video RAM for things like sprites, fonts, tiles, or possibly BOBs 5: A possible Video CPU interface, so that the main CPU doesn't have to babysit the blanking cycles and keep track of things like sprite placement or the screen window's place in the bitmap or tilemap. As for specific implementation projects, well, that's what this tread is for.
  9. Here are a few more perspective porting targets for Mr. Murray's latest software project: Exidy Sorcerer Sharp MZ Sharp X1/NEC PC88 (they both ran Microsoft Basic and CP/M and have similar port architectures. The biggest differences between them seem to be sound chips.) Sharp X68000 (Pretty sure there are porting projects for the Atari ST and Sinclair QL already under way) Apple Macintosh (System 3 or lower) Texas Instruments TI 99/4A Ohio Scientific Challenger Tatung Einstein series ColecoVision/Sega SG1000/ADAM/MSX1 (The specifications are so similar that a single build could theoretically be made, and then simply hand tweaked for each individual system). MSX 2, 2+, and Turbo R Commodore CBM 400+ machines (Successors to the PET) Fujitsu FM 8/7/77 (Architecture is close enough to the Tandy CoCo that the latter can be used as a preliminary code base)
  10. Wow, definitely getting late-stage Sonic series vibes from it. It seems like you're using every channel of the YM2151 for most of the instruments, at least three geometry synthesis channels in triangle and/or sawtooth for the base line, another two in white noise for the snares, and the PCM channel for the rest of the percussion. But I could be wrong...
  11. I just updated the published specs of the Mega65 on page 3.
  12. Well, maybe for the Xosera II, they could use a bigger FPGA to implement hardware sprites. Since this version doesn't seem to include the sound channels and FIFO, presumably that should leave some room in the FPGA for more features.
  13. I had this wild, wacky idea: There's this company, called Framework. Admittedly, their first model uses a 13.5 inch form factor with a previous-generation Mac Book style with all the problems that implies, and because the keyboard lacks a number pad means that the number line characters will need the shift key to put into functionality (which means slightly rewriting the BIOS ROM), and it simply won't be able to access PET peripherals without a specially made USB hub, (unless someone wants to try their hand at Centronics, PET Floppy, and Datasette expansion cards) and I don't know for certain if your current motherboard will fit into the chassis, but it looks like another option to look at for people considering similar projects.
  14. Well, for me, it would be: QuadPOKEY or X2 Phillips 1099 Yamaha YM2414+YM3012 DAC Seta X1-010 or Ensoniq DOC, DOC II, or OTIS
  15. Then again, there are a few "crochet hook" ideas that in hindsight, should have been dope slap obvious, but back in the day no one ever thought of. Take stacked RAM. The idea of stacking four to eight DRAM dies using through-silicon vias, plus DRAM refresh logic and possibly a DMA and/or MMU on a package no larger than a then-typical DIP should have been blindingly obvious, but it didn't happen. Done right, a 64K Pseudo-SRAM version should have drawn no more power and/or generated no more heat than an 8K SRAM on the same package, and massively reduced the chip count of, say, the Commodore 64 and subsequent follow-up motherboards. Unity Semiconductor, creators of CMOx Flash, was poised to turn the nonvolatile RAM market upside-down, but then they were bought out by Rambus, which scared all possible potential licensees off, due to Rambus' reputation as sharks. They had white papers that it could have been produced on conventional CMOS tools, and tested the concept at a five micron node.
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