Hardware YM2612 Interface

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TasuLife
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Hardware YM2612 Interface

Post by TasuLife » Mon Oct 27, 2008 2:59 am

Hey all.

I've been visiting this forum as a guest a whole lot in the past months,
mainly to read the ""authoritative reference on the YM2612" thread by Mr. Nemesis as reference to my project.

I've been working on a really simple circuit where a Pic Microcontroller
makes writes to a YM2612 chip, which in turn happily dumps out an audio signal.

The patch that is programmed is the "Grand Piano" that is defined at the bottom of the SEGA2.DOC Technical reference manual.

Last night I made the very first sounds, and tonight I have a C4 scale working.
This is not the end of the road for this project and I'll update this thread as I go.

Here are some unpolished demo videos of what I've done so far:

http://www.youtube.com/watch?v=p63t3O9LIsc
http://www.youtube.com/watch?v=TOsozYpKqhY

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TmEE co.(TM)
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Post by TmEE co.(TM) » Mon Oct 27, 2008 3:07 pm

Ha, nice, good work. I guess you're going to have a VGM player going on sometime ?
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TasuLife
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Post by TasuLife » Tue Oct 28, 2008 3:03 am

Yes absolutely. First, I'm going to get a midi interface finished, then I'd like to consider my options as to other protocols to follow.

here's what I've got on that as of tonite:
http://www.youtube.com/watch?v=0JSV9F905Fs

I dont really know any computer programming languages, so i'd like to do something embedded like putting VGM files on a SD card, then loading it up into this circuit. I know there are Fat16-decoder ICs that could make that approach do-able.


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Post by tomaitheous » Fri Oct 31, 2008 7:52 pm

Can I ask where you got the 2612 chip from? Are there still chips available? I had to remove one from one of Genesis systems ( :( ). I have it sitting on a PCE board and memory mapped to an open bus area.

Anyway, great project. I had plans to interface an MCU (8052 clone) to a different audio synth designs (doing my own PSG generating circuit too). Do you have any other pic related audio projects?

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Post by Shiru » Fri Oct 31, 2008 7:56 pm

tomaitheous wrote:Are there still chips available?
Yes, from chinese suppliers.

TasuLife
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Post by TasuLife » Sat Nov 01, 2008 11:58 pm

tomaitheous wrote:Can I ask where you got the 2612 chip from? Are there still chips available? I had to remove one from one of Genesis systems ( :( ). I have it sitting on a PCE board and memory mapped to an open bus area.

Anyway, great project. I had plans to interface an MCU (8052 clone) to a different audio synth designs (doing my own PSG generating circuit too). Do you have any other pic related audio projects?
First I'd like to say congrats on getting the YM2612 out of a genesis board. I tried doing this and only got a few pins desoldered (I also desoldered my fingers a few times).

I was lucky enough to find a parts distributor that had FIVE ym2612 chips in stock. that was at Quest Compoents - Quest does link to other companies that have thousands of YM2612 ICs, but I would imagine they have a high "minimum orders"... I actually had to order a bunch of other stuff from quest just to get up to their minimum order and get the chips.

Yes, this is my first audio project. The scope of this project is pretty large though.

Finally If you are documenting on your progress with the MCU project, I'd love to see what you have so far, please send me a pm.

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Nemesis
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Post by Nemesis » Tue Nov 04, 2008 3:40 am

A very interesting project! I wanted to build a mini test rig like this myself, but I had trouble figuring out all the parts I'd need to pull it off. Congrats on getting it working.
First I'd like to say congrats on getting the YM2612 out of a genesis board. I tried doing this and only got a few pins desoldered (I also desoldered my fingers a few times).
Having the right tools makes all the difference for jobs like this. I found desoldering virtually impossible until I got myself one of these little beauties:
Hakko 808 - http://search.ebay.com/360102920404
It makes desoldering chips like the YM2612 dead easy. For SMD desoldering, ChipQuik looks like a good way to go. I've got some on standby, but I haven't needed to do any SMD desoldering since I picked it up.

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Post by Shiru » Tue Nov 04, 2008 3:53 am

Nemesis wrote:I found desoldering virtually impossible until I got myself one of these little beauties
There is good old method how to easily desolder DIP components without special equipment and without damaging component and/or board. You need some old copper stranded wire, flux (solid or liquid) and soldering iron, of course. Put flux on wire, put wire on component pins, then heat each pin with soldering iron through wire. All solder moves to wire, leaving pins free. After removing the solder you can take component out of board.

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Nemesis
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Post by Nemesis » Tue Nov 04, 2008 4:20 am

Nifty. Kind of like home-made solder wick. I never did try that method. I tried solder-suckers and didn't have much luck. Well, I did get a chip off using a solder sucker, but it was an incredibly slow and difficult process. It's pretty hard to beat 3 seconds per pin though, which is about how long it takes with the Hakko 808.

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TmEE co.(TM)
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Post by TmEE co.(TM) » Tue Nov 04, 2008 11:04 am

I desoldered the YM2612 from my MD1 using a regular cheap 3$ soldering iron using the "heat and hit" method :P Heat one pin, hit the board on the desk, solder will fall off (or most of it). Repeat until all legs are free and remove the chip... slow, but if you have nothing better, its probably the only way.
Mida sa loed ? Nagunii aru ei saa ;)
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Post by tomaitheous » Tue Nov 04, 2008 3:50 pm

Haha - those are some interesting desoldering methods. TmEE, I've *never* heard of that method :D

I used a flat tip screw driver underneath the chip and put pressure outwards while heating each pin in series. It takes quite some time to do. I do have a heat gun and I usually heat the opposite side of the board as not to damage the chip, but it tends to heat up the surrounding area and not every practical for isolating a single chip.

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TmEE co.(TM)
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Post by TmEE co.(TM) » Tue Nov 04, 2008 9:22 pm

My dad taught me this 10 or so years ago :)
Its quite effective, I desoldered a 68000 from my dead MD1 clone that way, and its cartslot and all other chips.

I need a heat gun too...
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Post by Shiru » Tue Nov 04, 2008 9:35 pm

I used method similar to TmEE's sometimes, but rarely - cleaning floor from melted-in solder isn't so interesting. Difference is that I do not hit the board, instead I move it fast and stop immediately, so solder continues move by inertia and fly away from pins.

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TmEE co.(TM)
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Post by TmEE co.(TM) » Tue Nov 04, 2008 9:43 pm

hitting works better for 2 sided boards, and boards with tiny holes for chips... luckily I have no carpet on the floor, and the sloder splatters come off by just touching :)
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Post by SmartOne » Wed Nov 05, 2008 12:55 am

You guys should post a video of you performing this "hitting" or "shaking" method. I've never soldered, let alone de-soldered anything. It would be informative (and entertaining, as it sounds.) :P

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