Re: HardMPU, anyone?

Posted on 2017-09-18, 00:34

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

I'll probably test the build with a DE15 jack and a gameport adapter as I hate soldering D-Sub plugs. Personally, I bought some crimp DB9s just for this project because I too hate soldering D-Sub plugs. Also has the advantage that if one messes it up, there's a $3 tool that lets you non- …

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Re: HardMPU, anyone?

Posted on 2017-09-14, 04:14

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

Of course, the device itself is usually incomplete in an exercise of extreme cost cutting. https://karusisemus.wordpress.com/2017/01/02/cheap-usb-midi-cable-how-to-modify-it/ Wow! Well now I'm going to have to cut mine open and have a look. I haven't done any MIDI IN with it, so I wouldn't have …

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Re: HardMPU, anyone?

Posted on 2017-09-14, 01:27

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

Just saw the YouTube video. Very cool, and I'm glad it worked out for you "out of the box". Now I have a reason to dust off my Xi8088 and play some KQ4 :D It definitely completes the experience to run a homebuilt HardMPU in a homebuilt PC. Did you experience any stability issues with your Xi 8088? …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-09-10, 23:23

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Not seriously. I couldn't find sockets that worked with the resistor arrays well, so I never went any farther with the active terminator. I had some, but I have no idea where they came from. It was a long (30-pin?) SIP socket that I was able to cut into resistor-size sections. I've attached a …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-09-10, 18:01

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Anyone here still working on their Xi 8088 ? I spent some time building a MIDI card for mine (based on HardMPU, see the thread here at vogons) and developing a midi player. In general, I am capable of accomplishing useful work on the Xi 8088, though it continues to have strangely unpredictable …

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Re: HardMPU, anyone?

Posted on 2017-09-08, 15:10

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

Those look really nice. I'm surprised at the quick turnaround. I ended up building my own (what's wrong with me? I can't just wait a week or two???) based on the schematic checked into the github repo, and it worked. Not only that, but it worked perfectly on the first try. Very nice job with the …

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Re: HardMPU, anyone?

Posted on 2017-09-03, 01:15

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

My Intelligent Mode Midi Player is written and minimally tested in DOSBox. It causes DOSBox to make noise that sounds like music, though I haven't checked to see just how correct it is. There any many limitations, for example it doesn't support conductor yet, so there are no tempo changes or sysex …

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Re: HardMPU, anyone?

Posted on 2017-09-01, 16:17

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

I've never heard of an intelligent mode MIDI file player, but that certainly doesn't mean it doesn't exist. Please share with the class if you find one or write one. BTW, the HardMPU supports UART mode as well :D Thanks, I figured UART mode would be an available fallback. Intelligent mode would …

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Re: HardMPU, anyone?

Posted on 2017-08-31, 23:41

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

That's great news. In the meantime, I'd like to start collecting software. Never having had a MT-32 before (I was an AdLib owner), I'm assuming many of my old games (yes, I kept them all, from KQ1 on, every last game I ever bought) will work, but what about .MID music players? I can see there are …

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Re: HardMPU, anyone?

Posted on 2017-08-23, 15:19

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by smbaker

in Marvin \ Sound

in Marvin \ Sound

I'd be very interested in a bare PCB. I don't have my MT-32 yet; the primary thing holding me back in acquiring one is the lack of an MPU-401 intelligent interface that I could use on an XT-class machine. Last night I started thinking "how hard would it be to implement this in hardware using a …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-08-21, 00:52

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Spent some time playing with the active terminator board over the weekend. I configured my Xi 8088 using the buffered RAM daughterboards that I mentioned a page or two back. These boards will reliably prevent the Xi 8088 from booting unless the active terminator board is installed, so it was an easy …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-08-19, 17:42

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yesterdays reliability issues seem to have been resolved by unplugging the CPU card and plugging it back in. I wonder if the ISA connectors I used on the backplane are crappy? I seem to have had multiple issues that have been related to card/backplane issues, particularly with the CPU card.

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-08-18, 04:25

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The last thing I worked on was a speech synthesizer board, which was pretty successful. I'm still planning on building up a socketed active terminator so I can play with terminating various pins and figure out which lines the termination helps with and which it doesn't. I have all the parts …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-19, 15:16

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm ordering enough parts to build a second terminator with sockets rather than directly soldering the resistor packs, for easier troubleshooting, but will be a while before they get here... That's on my short list of things to do also. If nothing else, I'd like to know exactly which ISA bus lines …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-19, 03:25

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It may not have been what I thought it was... turns out the Xi 8088 wasn't seated well in the backplane. Just fussing with the card was giving intermittent boot failures. I'm not sure if it's something a little tweaked with my case, or if the bracket doesn't line up quite right, but I went ahead and …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-17, 15:22

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Any new developments, keenerb? Mine has started exhibiting a strange symptom today -- I bought an Avocent SVIP1020 KVM-IP to serve as my console, and the Xi 8088 starts behaving badly when the mouse cable is connected. This morning, about a dozen attempts couldn't get a successful boot out of it. …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-11, 16:09

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Just to see what would happen, I upped my oscillator from 24 Mhz to 30 Mhz. It's been successfully running checkit memory tests for about 24 hours. This is with the bus terminator board installed. Now, if only I could find a 36 Mhz oscillator... Scott

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-09, 23:31

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I haven't tried this with my Malinov backplane; is that what you're using? Yep, I have the Xi 8088 installed in the second slot from the left, and the terminator board installed in the rightmost slot. What value resistor did you choose? 220 ohm? One thing you could try is removing resistor packs …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-09, 21:25

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My xi8088 doesn't boot at all with the active terminator installed. No beeps, no video init, nothing. I verify 2.68v and 5v on the test points. *edit* I installed one of the capacitors in the wrong location. C9 is missing. *edit2* I moved the cap to C9, still nothing. You have it adjusted for 2.7 …

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Re: Xi 8088 by Segey Kiselev

Posted on 2017-06-08, 01:00

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by smbaker

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I am as well. I ended up grabbing a single-turn 10k resistor, so it's gonna be SUPER hard to tweak this sucker to 2.7v I'm afraid. You could try increasing the other resistor. The formula in the LT1118 data sheet is: Vout = Vfb (1 + R1/R2) + Ifb*R1 Vfb is 1.225V With R1 being the fixed resistor and …

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