VOGONS


Simmconn AWE64 Adapter

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Reply 220 of 548, by badmojo

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Some of those SIMMs get quite heavy - I'd be concerned that something like this would work its way loose and fall off (when the card was mounted on it's side, in a tower case).

It would be so nice if we could do-away with the old SIMMs altogether - they're big and getting harder to find. I have zero knowledge around the specifics but I'd be great if a modern memory chip could be mounted directly on the board. I'd be a much more compact design at least.

Life? Don't talk to me about life.

Reply 221 of 548, by gdjacobs

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It's likely the best way in terms of packaging. The expansion board could just be built with 32MB onboard. Sourcing compatible DRAM chips would be the most difficult thing. I'm not sure if the AWE64 supports dual rank SIMMs, but even if it does, FP mode or EDO DRAM chips with appropriate word capacity appear to be quite limited in availability these days.

I wonder if cannibalizing old SIMMs wouldn't be the most straightforward way, as I suspect most other avenues will lead back to the shadier parts of Shenzhen and parts of very dubious provenance.

All hail the Great Capacitor Brand Finder

Reply 222 of 548, by betamax80

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Seems like old news now, but I can confirm that the "GeneralUser" 28mb soundfont installed just fine and is working on my proto board.
Great to see you back in the discussion @Simmconn.

Reply 223 of 548, by SIMMConn

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dogchainx wrote:
Something along this line for TWO PCBs for the revival (extra PCB to hold current SimmConns as well as the current design) […]
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Something along this line for TWO PCBs for the revival (extra PCB to hold current SimmConns as well as the current design)

sEw2bVVl.png

Or this for an XL SimmConn

UxEjtPTl.png

Or this, just a big square and no "L"

NL8u1pwl.png

Anyways. Ideas. Very rough-draft, spitting ideas out of a brain running on 4 hours of sleep and LOTS of Dr. Pepper. You guys that do this so easily, I am thoroughly amazed.

Nice 3D rendering. What I meant is that once the SIMM can be installed on the same plane as the adapter, it doesn't need to stay clear the edge of the AWE64 board. The adapter will grow in length but not as much as in your diagram.

Reply 224 of 548, by SIMMConn

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@badmojo

It would be a 'no' for the idea of designing the FPM or EDO DRAM chip on the board directly. It requires much more advanced skills and expensive simulation tools to design the PCB layout. It will become a 4-layer board at least and cost will go up a lot, not to mention the scarcity of the FPM or EDO DRAM chips today.

@gdjacobs

It would also be a 'no' for substituting the FPM or EDO DRAM chip with modern DRAM chips. The modern DRAM chips (SDRAM, DDR/2/3/4) are all built on the same DRAM cells as the FPM or EDO, which have the most 'native' interface to the cells. The speed of the cells itself did not become faster over the years. The modern DRAM chips appear faster by paralleling and pipe-lining. The latency remains roughly the same. You always need to wait for 50ns to 60ns when accessing the first memory location, regardless of what DRAM you have. With FPM you need to wait the same amount of time to access the next location and so on, with EDO, SDRAM, DDR/2/3/4... waiting time to access the follow-on locations decreases. Adding a conversion interface to the modern DRAM chips to simulate FPM or EDO will only make the latency to access the first memory location longer, because the interface itself needs time to do the translation. You don't want to miss the first sample of every wave, do you?

Reply 225 of 548, by gdjacobs

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@SIMMConn

That was the sense I had as well. Who knows if you could buy or make a bridge device that was 1) quick enough and 2) cheap enough to be worth using? My concern wasn't so much with timing, but rather with the complexity of buffering and signal conversion.

Async DRAM chips are available, but the prices in realistic volumes appear to rival what costs were when FPM was new technology. At first blush, I didn't perceive timing here to be as much of an issue as supply given the modest clock FPM operates under. However, I haven't really delved into low level DRAM EE since wiring up TTL ALUs and DRAM for fun, years ago.

Anyway, I'm here to learn. So, please continue!

All hail the Great Capacitor Brand Finder

Reply 226 of 548, by Rawrl

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dogchainx wrote:
Something along this line for TWO PCBs for the revival (extra PCB to hold current SimmConns as well as the current design) […]
Show full quote

Something along this line for TWO PCBs for the revival (extra PCB to hold current SimmConns as well as the current design)

sEw2bVVl.png

Or this for an XL SimmConn

UxEjtPTl.png

Or this, just a big square and no "L"

NL8u1pwl.png

Anyways. Ideas. Very rough-draft, spitting ideas out of a brain running on 4 hours of sleep and LOTS of Dr. Pepper. You guys that do this so easily, I am thoroughly amazed.

Wouldn't it be better to rotate the SIMM socket 90 degrees, so it's not hanging so far off the connector? Would that cause issues with trace routing and length? The only other problem I could foresee would be with the width of the SIMM versus the height of the case.

Reply 227 of 548, by the Goat

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Rawrl wrote:

Wouldn't it be better to rotate the SIMM socket 90 degrees, so it's not hanging so far off the connector? Would that cause issues with trace routing and length? The only other problem I could foresee would be with the width of the SIMM versus the height of the case.

A 30 pin SIMM fits vertically on a full height expansion card. But a 72 pin SIMM is too long I believe.

Reply 228 of 548, by dreamblaster

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hi
I will make 5 more simmconn assembled and programmed boards this weekend.
pm me if interested.

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
New X2GS sound card : https://www.serdashop.com/X2GS
Thanks for your support !

Reply 229 of 548, by dreamblaster

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okay all simmcon revival boards reserved.
if there is sufficient interest I will make a few more

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
New X2GS sound card : https://www.serdashop.com/X2GS
Thanks for your support !

Reply 232 of 548, by hard1k

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I would be more than interested if the issue with the adjacent card is resolved somehow.

Fortex, the A3D & XG/OPL3 accelerator (Vortex 2 + YMF744 combo sound card)
AWE64 Legacy
Please have a look at my wishlist (hosted on Amibay)

Reply 236 of 548, by gerwin

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Nice work, as always! If you happen to have one SimmConn to spare in the future, maybe I should upgrade my dusty AWE64Gold.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 238 of 548, by dreamblaster

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okay, I will make more, it will take some time to get the parts and pcb's, for one more batch.
It would be nice to know the quantity.

At this moment this is 'vogons only' limited edition, no plan to add it to the webshop.
so pm me the details if you are interested, and which types you want : gold', 'value' or 'universal'
(please note 'universal' is currently under test, expect more feedback this week, so better to wait)
I will make sure to make sufficient for everyone, but probably make only this one batch,
so keep in mind to get what you need now.

pricing will be :
solder kit : 30 euro + 5 euro shipping (you need to be able to solder SMD as well. Have a look at the photos, the PLCC20 is not so easy.)
fully soldered : 40 euro + 5 euro shipping (normally hand soldered by me, limited amount, or if sufficient quantity, i may consider having a batch machine soldered, which may look nicer).

If you need other serdashop stuff in the same shipping, you can also let me know
so I can combine in 1 shipment (and save out additional shipping cost).

Visit http://www.serdashop.com for retro sound cards, video converters, ...
OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
New X2GS sound card : https://www.serdashop.com/X2GS
Thanks for your support !