VOGONS


Internal OPL3 ISA 8 bits (PCXT)

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First post, by spark2k06

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I designed a new low profile OPL3 sound card from the scheme provided by the existing TexElec Resound OPL3 in which, as you can see, it is a four-channel sound card based on the Yamaha's YMF262 chip and use of two high quality WIMA film capacitors per channel to prevent the passage of direct current in the audio output.

In this case, I thought that with the two primary channels it is more than enough. On the other hand, I have replaced the port selection DIP with one of 2 switches, to select with the help of an SPLD only four possible ports, including the default 388h used by Adlib and the 220h to "cheat" some games pretending to be a Sound Blaster ... I think the rest is too much and they are still purely experimental, with this measure I also gain some space and eliminate other chips involved in this task:

ACtC-3dmK6CX6wowt9rvT-Y_j6EPMeTt7iWx3HanmwpA6XsztT2AOXmAaZLwKG0_JHV-aiqTLtrZsfYYp1Ivw_oRRuCkiWRlxpzTf3i8kksiJYvW3z7JnD_sFwWb4eFeYheXDv4rVh6FIXjMrgUTl_gwn_5aEg=w1255-h779-no

As you can see, I have also decided to make it internal regardless of the external audio jack in order to be used in current PC cases that have the typical USB + Audio connector on the front, so that a bracket is not necessary , being enough with one of the blind brackets that come standard with the box.

I have launched with this project to provide a sound card to my NuXT Monotech tucked into a low profile desktop, although it could be used in any other PCXT and compatible.

Version 1.2 Kikad project available here.

Warning: For now, I am deleted Kicad sources from repository. Only available schematic in PDF format, in the same way as Texelec.

Last edited by spark2k06 on 2020-08-05, 06:04. Edited 11 times in total.

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Reply 1 of 23, by Grzyb

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spark2k06 wrote on 2020-02-03, 08:42:

four possible ports, including the default 388h used by Adlib and the 220h to "cheat" some games pretending to be a Sound Blaster

SB decodes OPL at both 38x and 2xx.
If you want SB compatibility, I would recommend one jumper to enable/disable 38x, and separate jumper(s) to select 22x/24x/...

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 2 of 23, by spark2k06

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Grzyb wrote on 2020-02-03, 12:38:
spark2k06 wrote on 2020-02-03, 08:42:

four possible ports, including the default 388h used by Adlib and the 220h to "cheat" some games pretending to be a Sound Blaster

SB decodes OPL at both 38x and 2xx.
If you want SB compatibility, I would recommend one jumper to enable/disable 38x, and separate jumper(s) to select 22x/24x/...

You mean SB uses both ports (38x and 2xx) at the same time?

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Reply 3 of 23, by Tiido

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There's 3 ranges used by SB cards. 2x0...2x3 for OPL3/SAA, 2x8...2x9 for OPL2 and 388...389/38B for OPL2/3.

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Reply 4 of 23, by spark2k06

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The configuration is done with the SPLD, and in principle I did not want to touch the design of the PCB unless it was strictly necessary, although the silkscreen of the DIP Switch could be modified according to the SPLD programming, where I can set the I/O ports, or to use several at the same time if necessary ... any suggestions in this regard?

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Reply 5 of 23, by spark2k06

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Well, according to this website the ports are:

220h or 240h (selectable) and 388h -> Sound Blaster Pro II, 16, 32, AWE32/64 and Live, ESS 688, etc.

Only 388h -> Adlib Gold, Windows Sound System

So in the SPLD I will always keep the 388h present and leave the DIP Switch configuration such that:

* 0 - 0 Only 388h (Adlib Gold)
* 0 - 1 388h + 220h (Sound Blaster)
* 1 - 0 388h + 240h (Sound Blaster)
* 1 - 1 388h + 260h (Sound Blaster)

So as for the design of the PCB, I just have to update the silkscreen.

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Reply 6 of 23, by Grzyb

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Some people might want to use that OPL3 card together with something else, most likely SB 1.x/2.0
So it would be nice to be able to disable the 38x port range...

38x and 22x - SB with OPL2, CMS, DSP
24x - OPL3

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 7 of 23, by spark2k06

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Grzyb wrote on 2020-02-03, 15:53:
Some people might want to use that OPL3 card together with something else, most likely SB 1.x/2.0 So it would be nice to be able […]
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Some people might want to use that OPL3 card together with something else, most likely SB 1.x/2.0
So it would be nice to be able to disable the 38x port range...

38x and 22x - SB with OPL2, CMS, DSP
24x - OPL3

So, such a configuration could cover all the needs ?:

0 - 0: 388h
0 - 1: 220h + 388h
1 - 0: 220h
1 - 1: 240h

However, since the SPLD will be in socket any programmer can reconfigure it as best suits your needs, obviously the silkscreen will no longer serve as a reference.

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Reply 8 of 23, by Grzyb

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spark2k06 wrote on 2020-02-03, 16:20:
So, such a configuration could cover all the needs ?: […]
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So, such a configuration could cover all the needs ?:

0 - 0: 388h
0 - 1: 220h + 388h
1 - 0: 220h
1 - 1: 240h

Yes, seems OK to me.

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 9 of 23, by BinaryDemon

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Interesting project, why is 'fake soundblaster' desirable? I find it difficult to believe there is software that you would run on an XT class machine that supports Sound Blaster but not Adlib. Maybe homebrew software?

Check out DOSBox Distro:

https://sites.google.com/site/dosboxdistro/ [*]

a lightweight Linux distro (tinycore) which boots off a usb flash drive and goes straight to DOSBox.

Make your dos retrogaming experience portable!

Reply 11 of 23, by Grzyb

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BTW: that "Adlib Gold" is misleading, may suggest the card is compatible with Gold, which of course isn't true - just "Adlib" would be better

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 13 of 23, by Grzyb

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spark2k06 wrote on 2020-02-03, 21:22:

Adlib alone, either ... because it is OPL2. Adlib Gold FM, maybe?

Well, "Adlib Gold FM" is correct, but then you would need to rename the second option to "SB Pro 2 or later FM"...

Nie tylko, jak widzicie, w tym trudność, że nie zdołacie wejść na moją górę, lecz i w tym, że ja do was cały zejść nie mogę, gdyż schodząc, gubię po drodze to, co miałem donieść.

Reply 14 of 23, by Jo22

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BinaryDemon wrote on 2020-02-03, 18:53:

Interesting project, why is 'fake soundblaster' desirable? I find it difficult to believe there is software that you would run on an XT class machine that supports Sound Blaster but not Adlib. Maybe homebrew software?

"Homebrew".. 🙄 No offense, though from what I remember, back in the day (90s) that kind of software was the most common type of software of all. 😀
It was called Public Domain, Freeware and Shareware and was written by individuals and one-man companies. Tens of thousands of these little games were out there in the wild,
many still unknown, with the most popular being distributed on Shareware CD-ROMs (also known as "shovelware" or something like that).
If we look at it that way, these people likely wrote their own games with their own Sound Blaster compatible card in mind, rather the obsolete AdLib from the 80s.
In addition, there were a few books available that covered the Sound Blasters. And these were advertised in PC and video games magazines a few times.
Nowadays, someone would call them "indie" game developers or something along these lines. 😁
The makers of Cave Story, Tower of Heaven or Undertale may fall into that category, also.

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Reply 15 of 23, by BinaryDemon

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Fair enough, I didnt see any of that until I started connecting to BBS's in 1993. I guess I was always more interested in commercial software than indie software.

Check out DOSBox Distro:

https://sites.google.com/site/dosboxdistro/ [*]

a lightweight Linux distro (tinycore) which boots off a usb flash drive and goes straight to DOSBox.

Make your dos retrogaming experience portable!

Reply 18 of 23, by Cyrix200+

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Looks and sounds great!

1982 to 2001

Reply 19 of 23, by spark2k06

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Version 1.2 Kikad project available here.

- Modification of YMF762 and YAC512 footprint dimensions

- Increased thickness of some power tracks

- Silkscreen of 74HC245 changed to 74HCT245

- Added two resistors in the back layer to solve the problem of version 1.0

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