VOGONS


First post, by Electronic Genets

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Is there any interesting thing in the CSM mode of OPL2 (abandoned in OPL3)? I cannot find any documentation to this mode other than short description that was used to obtain "composited voices".

What registers should it controlled after it was turned on? This mode is unimplemented in known emulators.

Author of the DINO-2e OPL2-like emulator.
DINO-2e is not OPL2 emulator.

Reply 1 of 6, by Jo22

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Hi, I'm just a layman, but I think Composite Speech Mode was primarily used in Japan or Japanese systems.
Didn't have the OPL1 , CSM, too ? I haven't really checked, it's just a vague memory.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 2 of 6, by Electronic Genets

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Jo22 wrote:

Composite Speech Mode

Was it a speech synthesizer? If Yes it will be very interesting to me to implement it but I need data/documents to do it.

I have no OPL1/OPL2 or OPL3 chip now.

After searching "Composite Speech Mode" (I found Composite Sine Mode) I was found that timer 1 was used to trigger KEY-ON on all channels. It is only one difference to non-CSM mode? For new faster computers and faster write OPL3 algorithm (no needed delay after OUT opcode) this mode will be unnecessary if it is only one difference.

https://retrocomputing.stackexchange.com/ques … rk?fr=operanews

Justme @ StackExchange wrote:

The documentation fails to mention which channels are used for the CSM mode, so I can't currently provide more detailed information without further reverse-engineering.

It is a pity that s/he did not link to the documentation s/he uses... This is how knowledge on the Internet is lost.

Author of the DINO-2e OPL2-like emulator.
DINO-2e is not OPL2 emulator.

Reply 3 of 6, by Jo22

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Hi again. 🙂
You're right, it's a sinusoidal synthesis. One of its applications was speech synthesis also, I think.
The CSM seems to be taken over from OPL aka OPL1 (YM3526) chip.
- I've attached a datasheet for your, it's very basic, though. 🙁

The OPL2 version seems to be available here.

Attachments

  • Filename
    yamaha_ym3526.pdf
    File size
    1.31 MiB
    Downloads
    8 downloads
    File license
    Fair use/fair dealing exception

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 4 of 6, by Electronic Genets

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Thank you Jo22. I will look at it. If there will be something interesting and leaving questions, I return to this thread.

Edit: these documentations are very thin. There are no word about CSM. You can only read CSM means "Composite Speech synthesis", register 08, bit 0x80. No more... My question is still valid.

I have old detailed documentation for YM3812 (OPL2) including attack and decay tables, explaining what 3db/octave means with table but the CSM/CSW is also not described.

To Administrator: please add this documentation as attachment. I have blocked attachments more than 5MB. It is very detailed spec for Yamaha YM3812. It will useful for more users but it on the verge of being forgotten. Each newer version is shorten. Ufile.io deletes files after 30 days.

Author of the DINO-2e OPL2-like emulator.
DINO-2e is not OPL2 emulator.

Reply 6 of 6, by Jo22

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Found something. There was an older Vogons thread about CSM/CSW -> Does anyone know what OPL2 "composite sine mode" even is, or what used it?

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//