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HardMPU, anyone?

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Reply 80 of 608, by ab0tj

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dogchainx wrote:

So how would this interface to external MIDI (MT32, etc)? Joystick/midi-type port?

It will be using an identical cable to what keropi's clone will be using, DE9 to DIN.

Reply 81 of 608, by ab0tj

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Prototype almost done... More testing after it's fully wired.

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Reply 82 of 608, by dogchainx

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Love it.

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Reply 83 of 608, by ab0tj

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Prototype all finished up. Now back to software debugging.

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Reply 85 of 608, by ab0tj

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Thank you!

In other news, the git repo has been updated with a software version that does not have the hanging notes bug. More testing will be done to verify all intelligent mode functions are working correctly. If so, I'll start on making delayed SysEx and the other nice little SoftMPU features work. Basically, I just have to work out a way to turn the features on and off. I'm thinking I will find some unused MPU401 commands and use a small DOS program to send them to the board to enable or disable features.

Reply 87 of 608, by dogchainx

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What would it take to put on a wavetable connector? 😀

386DX-40MHz-8MB-540MB+428MB+Speedstar64@2MB+SoundBlaster Pro+MT-32/MKII
486DX2-66Mhz-16MB-4.3GB+SpeedStar64 VLB DRAM 2MB+AWE32/SB16+SCB-55
MY BLOG RETRO PC BLOG: https://bitbyted.wordpress.com/

Reply 88 of 608, by stamasd

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dogchainx wrote:

What would it take to put on a wavetable connector? 😀

It would take adding audio circuitry, since the card has none. It's just an interface.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 89 of 608, by PhilsComputerLab

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ab0tj wrote:

Prototype almost done... More testing after it's fully wired.

Looks very nice, great job!

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Reply 90 of 608, by alexanrs

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stamasd wrote:
dogchainx wrote:

What would it take to put on a wavetable connector? 😀

It would take adding audio circuitry, since the card has none. It's just an interface.

Not much, really. The waveblaster already delivers the analog audio, see the pinout here. The biggest issue would be that I have no idea how to separate the analog ground and the digital ground to prevent bus noise issues, but that's it. Just route the audio out pins to a Line Out plug or a LGRG or LGGR header (I don't remember which one cards expect in their AUX internal connector) and plug that into the sound card. If someone wants to use this as a stand-alone card then the whole analog circuitry, with the amplifier and everything, would have to be developed.

Reply 91 of 608, by stamasd

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Adding an amplifier and a headphone jack is trivial. I've made dozens of these CMoy mini-amps that are powerful enough to drive earbuds comfortably; if you add a power amp or a current buffer you can drive speakers easily. They don't take much real estate on a PCB and sound really good if you choose the amp wisely.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 92 of 608, by PhilsComputerLab

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I'd prefer this card to stay minimalistic / clean and do one purpose well. There are so many sound cards with wavetable headers. You can also get wavetable devices like this one: http://www.serdashop.com/MIDIBOARDCHILL

Also there are no LA synthesis wavetable modules, which this intelligent mode interface is really geared towards.

But that's just me.

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Reply 93 of 608, by alexanrs

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philscomputerlab wrote:

I'd prefer this card to stay minimalistic / clean and do one purpose well. There are so many sound cards with wavetable headers. You can also get wavetable devices like this one: http://www.serdashop.com/MIDIBOARDCHILL

Also there are no LA synthesis wavetable modules, which this intelligent mode interface is really geared towards.

But that's just me.

A MIDI card with a waveblaster connector could be the perfect pair for a Sound Blaster 16/AWE32+OPL3 with the hanging note bug. Sure, then the "intelligent" aspect of it stops being as important (except for games that use only the default instruments of the MT-32, like Monkey Island - it sounds fine on my DB50XG), but you get a more convenent setup than having to juggle with multiple sound cards in the same system. I do believe, though, that the main project should remain a minimalistic/clean and that the wavetable header can be added in a "fork" by people that might benefit from it.

Reply 94 of 608, by PhilsComputerLab

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Yes, but you can grab one from many, existing, sound cards and do exactly what you're after. Forking sound like a good idea though.

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Reply 95 of 608, by ab0tj

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I seem to be having trouble with large SysEx transfers, such as when King's Quest V loads the custom sounds into the MT-32. No errors are displayed on the MT-32, but it sounds like the SysEx is not taking effect. So, still continuing with the debugging. On the bright side, King's Quest IV works great.

Reply 96 of 608, by PhilsComputerLab

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ab0tj wrote:

I seem to be having trouble with large SysEx transfers, such as when King's Quest V loads the custom sounds into the MT-32. No errors are displayed on the MT-32, but it sounds like the SysEx is not taking effect. So, still continuing with the debugging. On the bright side, King's Quest IV works great.

I'm curious what computer you are using to test games?

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Reply 98 of 608, by stamasd

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I agree with the "no combining" this with anything else. It should be an intelligent MPU-401 interface and nothing else. The design is open and adding any extras would be an exercise for the reader.

Like the wavetable header noted above. It would take a 26-pin header, 2-6 ICs (depending on the level of distortion and output power you want) and a few resistors/caps plus an audio jack to make it happen. But that adds manufacturing cost and takes real estate on the board especially since the audio and digital parts should be well separated and shielded against each other. Better KISS (keep it simple, stupid) and have this be the ultimate MPU-401 interface period.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 99 of 608, by ab0tj

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philscomputerlab wrote:

I'm curious what computer you are using to test games?

It's a K6-III+ machine. Using SetMul to slow things down doesn't really change anything. I'm pretty sure it's due to a problem in the code, as skipping the function that looks at the MIDI data being sent to keep track of SysEx, etc, and just sending the byte straight out the MIDI port works fine. Though, that function is exactly the same as what is used in SoftMPU as far as I can tell, and SoftMPU works fine for KQ V.