Re: Sonic Buster 8: A new 8-bit ISA sound card

Posted on 2024-04-17, 19:45

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

No prototype is complete without big bodges hahaha I have done a FIFO on FM chips before, it works very well but I used a FPGA + its internal memory for that. There are actual FIFO chips out ther but the logic necessary can be quite big to utilize them... You can avoid garbage sounds etc. by …

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Re: List of VLB IDE Controllers

Posted on 2024-04-16, 21:59

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It is a CPLD there, something on the level of a much souped up 20V8 PAL chip. Judging from the connections which are mostly IDE control signals, it perhaps helps with the DMA modes.

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Re: Roland RA-50 Mod

Posted on 2024-04-16, 18:20

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You also need the CPU program ROM of CM32L to actually have the extra sounds usable, the ROM already there will not know anything about the extra sounds. You can also use a 27C801 or some other 1MByte EPROM and a wire from A19 to the EPROM A19 to get the full sample set without needing to split …

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Re: Video from 486 Sometimes in Black/White

Posted on 2024-04-16, 15:47

by

by Tiido

in Marvin \ Video

in Marvin \ Video

Every time I have seen this type of problem it is always because of monitor detection pins vs DDC type issue. In the end I mod the video card so it always detects a color monitor. KVM might get in the way of the detection method in video card vs monitor alone, you can plug in monitor directly and …

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Re: What is this 8bit ISA Card? (Help me identify it)

Posted on 2024-04-16, 05:24

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It looks to me it is a VGA to TV (via cvbs + s-video) card. CXA1145 is for converting RGB to those two formats. CXD1172 are ADCs, CS82LB01 are combination of frame storage and processing, uPC666 are DACs. There are two 4046 PLL chips and I suppose the PLDs with the logic chips make for all the …

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Re: What does it take to replace an Intel 10 MHz 286 with a Harris 12 MHz 286? Hopefully... nothing?

Posted on 2024-04-14, 06:55

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

HMOS is intel's trademark for their own depletion-load NMOS process, everyone else had something like it too. All Intel's 286 CPUs were in one of the HMOS processes and run like little furnaces 🤣

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Re: Let's improve video output quality of VGA ISA/VLB cards (First success !)

Posted on 2024-04-13, 23:29

by

by Tiido

in Marvin \ Video

in Marvin \ Video

Excellent, another way to get better results ~

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Re: What does it take to replace an Intel 10 MHz 286 with a Harris 12 MHz 286? Hopefully... nothing?

Posted on 2024-04-13, 14:38

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Most of these machines have a NMOS 286 which is like a little furnace. If that 12MHz Harris part is a CMOS one, it'll run waaaay cooler. This is one thing I will do in my Toshiba T3200 once I replace the LCC with PLCC socket in it, I may not get more speed but I definitely get less heat/power use.

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Re: What retro activity did you get up to today?

Posted on 2024-04-13, 02:33

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for confirming, that makes sense since it'd be an effects processor? I don't think I've ever seen a cooked EMU8000 chip although I've only got later SB32 and AWE64 cards, perhaps those are less toasty. Not just effects but all of the sound generation. The other big chip is just the CPU …

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Re: What retro activity did you get up to today?

Posted on 2024-04-12, 21:56

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've been doing the same thing today on my slot 1 test bench setup - testing out the Yamaha DB50XG that I got inside of a computer I bought recently. I thought it had some fault because the main chip gets relatively hot going up to 60c? 1712874066305_100.JPG The main sound chip does get quite …

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Re: SimCity Classic - corrupt font

Posted on 2024-04-12, 19:00

by

by Tiido

in Marvin \ Software

in Marvin \ Software

As far as I know, it is due to the VGA BIOS lacking 8x14 font in it, which a lot of later chipsets started to omit to make room for things like VESA stuff. I think there is a TSR somewhere that helps to fix this issue but I don't remember any details unfortunately.

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Re: What does it take to replace an Intel 10 MHz 286 with a Harris 12 MHz 286? Hopefully... nothing?

Posted on 2024-04-12, 18:10

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It should just be a matter of replacing the chip, and if the original CPU isn't an LCC version it should be quite easy.

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Re: PicoGUS: ISA sound card emulator with Raspberry Pi Pico (Gravis Ultrasound, AdLib, MPU-401, Tandy, CMS)

Posted on 2024-04-11, 02:26

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Much easier because there's no MCU to emulate, just some registers and state machines.

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Re: Throttle Blaster

Posted on 2024-04-09, 21:52

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This method of speed control is really clever ! Very very flexible ~

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Re: Can a faster ISA Graphics card be built?

Posted on 2024-04-09, 21:28

by

by Tiido

in Marvin \ Video

in Marvin \ Video

Not really. On the PC, there is no "line cache", so each text line needs to be retrieved for each scan line of the character. For example, on CGA, in high-res text mode, a character takes 8 pixels at 14.318MHz pixel clock, which is 1.8 megacharacters/second....... I primarly wrote about the idea of …

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Re: Can a faster ISA Graphics card be built?

Posted on 2024-04-09, 09:55

by

by Tiido

in Marvin \ Video

in Marvin \ Video

A shared memory architecture, isn't that something the PC Jr did use once ? But without fast, dual-ported chips? Generaly speaking, assuming that the CPU and graphics chip would be on same die or chip, like with Cyrix MediaGX (?) or Mx Macs, couldn't this be also an advantage at some point ? I …

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Re: SC-88 Pro - Intro of MIDI files are always delayed

Posted on 2024-04-08, 23:09

by

by Tiido

in Marvin \ Sound

in Marvin \ Sound

Does it happen with all files or just some ? A number of files make a lot of MIDI parameter updates during startup and saturate the bandwidth of MIDI UART link. Such files are softsynth and USB connection orientated, where this problem will not be happening.

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Re: Can a faster ISA Graphics card be built?

Posted on 2024-04-08, 22:27

by

by Tiido

in Marvin \ Video

in Marvin \ Video

There's the big complication that the memory bus is usually unavailable, always accessed by the CPU so it is actually difficult to use that data, without some sort of a complicated dual part mechanism that arbitrates the accesses on both sides. Video memory buses are just as busy as any CPU buses …

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Re: "TRL" CRT Horizontal Position issue

Posted on 2024-04-08, 21:53

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hahahah, wow, this monitor made a really valiant effort to show a low resolution source then, now that it is found out it is a VGA monitor instead.

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Re: Do these motherboard caps look ok?

Posted on 2024-04-07, 22:15

by

by Tiido

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Visually these are all fine. Sanyo uses this kind of vent for example, and a number of chinese capacitors... If they are sanyo's they're likely ok, I actually couldn't see any branding on them. This board should predate the capacitor plague so unless you actually have problems, perhaps it isn't …

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