Re: MPU-401/Compatible UART-mode Buffer Reference

Posted on 2017-07-15, 13:31

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

So a MIDI interface will have to store anything it receives in a buffer, so that it can wait there for the host to read it. Using a 1-byte buffer on that side is quite a risk on very slow computers I'd say. On modern computers you'd get away with it, because you could put a host-side buffer on it: …

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Re: YMF262 design flaw

Posted on 2017-07-14, 20:49

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

That is very exciting info, I am so amazed/stunned by this. I'll definitely try these after I've tested the attack rate thing. I've been thinking if this is the correct way to test it: -initialize all registers so chip produces dead flat zero value silence -configure one channel so that only one …

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Re: 486 and Roland MT32

Posted on 2017-07-13, 08:13

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

Hi there, I'm trying to connect my Roland MT32 to a 486 PC. My soundcard is a Pro Audio Spectrum 16. According to my research the gameport is MPU401-compatible. I've got a midi-cable connected to the gameport and the midi in/out of the midi-cable to the MT32. I tried plugging in a headphone into …

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Re: YMF262 design flaw

Posted on 2017-07-12, 19:48

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

figured out exact rhythm mode algorithm(appearantly noise generator updates every internal cycle, which equals to Master clock/8. Noise polynomial is simpler than was in MAME: x^23+x^14+1), checked KSL calculation. YMF262 has 16 LSI test bits. Some of them enable test data output through TEST pin(I …

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Re: YMF262 design flaw

Posted on 2017-07-12, 18:00

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

I'll put it on my todo list but I can't make any estimate when that will happen. Meanwhile, can you provide some information about this die shot reverse engineering, I'd be happy to read and maybe comment on something, although my experience is only limited to figuring out OPL2 KSL lookup table …

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Re: Another question about BIOS, FDISK and hard disk size

Posted on 2017-07-11, 22:09

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sometimes the BIOS will just print detected values that also read on the hard drive but can't really understand so big amount of cylinders, it may wrap at some point. Clearly if it would only have NORMAL support it could not perform geometry translation so it will be limited to 1024 cylinders, 16 …

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Re: Looking for a 9700 pro owner with eletronic knowledge

Posted on 2017-07-09, 15:53

by

by Jepael

in Marvin \ Video

in Marvin \ Video

I don't own one and that's a bad photo, but from other photos on the net I figured that's a power supply bypass capacitor for the 74ACT08 AND gate right next to it. The capacitor value is not that critical, it most likely could be 10nF or 100nF, and such capacitances are next to impossible measure …

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Re: IDE Command protocol

Posted on 2017-07-07, 22:26

by

by Jepael

in PC Emulation

in PC Emulation

I would have suggested older ATA specifications and OSDEV articles/examples about ATA storage devices.

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Re: self built covox produces static

Posted on 2017-07-07, 22:16

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by Jepael

in Marvin \ Sound

in Marvin \ Sound

Hi all! I have just finished building a Covox plug (I have used the schematics provided on Wikipedia). I have double checked the circuit, it looks fine according to the schematics, however it produces a crap ton of static hiss with everything I tried. I have tried some games, and Inertia Player. …

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Re: Asus P/I-P55T2P4 CPU jumper wire?

Posted on 2017-07-07, 21:56

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It only has two multiplier select jumpers BF0 and BF1, so you need the mod for third jumper BF2 so you can get certain K6 CPUs to run at correct frequency with certain FSBs because standard two jumpers kind of expected you had a certain FSBs available. Back in the day I owned a T2P4 (forgot which …

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Re: -5v in layman's terms?

Posted on 2017-07-07, 21:06

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can someone explain this concept in layman's terms? Why does the soundcard need a -5v rail? What is the difference between positive and negative in this instance? Concept: 1.5V batteries and speaker cone movement. Basically, while you can use just a single 1.5V battery and decide if you want to use …

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Re: Repairing audio cards?

Posted on 2017-07-06, 12:59

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There are many things that could be potentially causing trouble here. I'd check caps and xtals first. ;) There is no simple way to go at it for someone not active in the EE field. Ok. This may sound like a fool's question, but.. What is EE ? It's not an abbreviation for Emperor of the Electron , …

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Re: PCI-X graphics, anyone?

Posted on 2017-07-05, 21:02

by

by Jepael

in Marvin \ Video

in Marvin \ Video

koverhbarc wrote: How, exactly? I assume those extra pins are there for a reason and may as well be used; these 64-bit cards might have the fastest 2D speed of all. For example the Parhelia was 64-bit at only 66MHz bus speed. That's equivalent to AGP 2x only.

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Re: More then one cd drive or sound card and cd audio?

Posted on 2017-07-05, 20:27

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by Jepael

in Marvin \ Sound

in Marvin \ Sound

Just to clarify few things about line-level analog audio: 1) it is usually OK to drive multiple inputs from one source (can connect one CD drive to 2-3 sound cards easily) 2) it is usually NOT OK to connect multiple outputs together (even if one output is not playing anything, it's still NOT OK. Two …

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Re: Ancient SCSI controller card ?

Posted on 2017-07-04, 18:14

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Eh, did you google "WANGTEK ASSY 30850"? It's a tape drive controller for QIC-36 type drives. http://www.sprague.ws/library/pc36iii.jpg

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Re: DOS 6.22 onto hard drive from different computer

Posted on 2017-07-04, 14:27

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If you have a CD drive, making a bootable CD from the boot floppy is all you need as long as the boot floppy has enough tools. I recall I made a bootable MSDOS floppy image with all necessary tools to partition a hard drive, format it, and transfer system files (fdisk, format, sys), and some way to …

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Re: Memory for protected mode DOS games

Posted on 2017-06-24, 22:23

by

by Jepael

in DOS

in DOS

Does the Day of The Tentacle run on a 8086 or 80186 CPU? If it doesn't, it needs a 80286 to work(since it won't run 80286+ instructions on those CPUs). The 80286 only adds new instructions for entering and managing protected mode, so if it doesn't use Protected Mode, it should run on a 8086 or …

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Re: The Tandy 1000 ISA sound card brainstorm thread.

Posted on 2017-06-19, 21:32

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I don't think the microcontroller would work so well. Except maybe if all sound chip pins are multiplexed to the separate MCU. The hard part is not to code the program, but determine how to mux those pins (few more chips) and how to write the program into MCU flash in the first place (OK, modern …

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Re: Running monkey island with sb + mt32 on a 286

Posted on 2017-06-19, 19:22

by

by Jepael

in Marvin \ Sound

in Marvin \ Sound

Softmpu won't work on a 286 CPU, that's where you need a real MPU or compatible card. It's not about EMM as memory, it's about trapping IO port accesses, which is a feature of 386 CPU that can be most easily requested from EMM memory managers such as EMM386 or QEMM as they run the CPU in virtual 86 …

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Re: 8 bit RTC card : what are these components ?

Posted on 2017-06-14, 16:17

by

by Jepael

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

They are tantalum caps, 10uF 25V. They short quite easily when old enough.

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