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1088XEL Alternative Mother-Board Project

Alernative Motherboard Redesign New Advanced Atari 8-bit

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#51 mytekcontrols OFFLINE  

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Posted Wed Jan 18, 2017 5:06 PM

I believe this is the layout that has already been implemented when using DA15 for SIO connectors.

 

attachicon.gifDA15-SIO.gif

 

I checked the Sdrive Nuxx schematic and it does use this method. He made the PCB with footprints for both SIO/DA15 connectors, either can be installed. I would suggest doing the same, giving the end user the choice of which connector to use.

 

 

Thanks BillC  :)

 

Unless I'm mistaken that looks the same as what I am implementing, but I'll double check that a bit later to be sure. And it makes perfect sense for me to duplicate it (would also be kind of dumb to create yet another variation).

 

Thanks again for posting this information.

 

- Michael


Edited by mytekcontrols, Wed Jan 18, 2017 5:07 PM.


#52 mytekcontrols OFFLINE  

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Posted Thu Jan 19, 2017 1:49 AM

Based on BillC's post, I have modified my schematic to match the Sdrive Nuxx SIO connection options.

 

zijrCF1.pngpost-26063-0-28352100-1484778437.gif

So now it includes both the D-Sub 15 male along with the standard Atari SIO jack on the PCB, thus allowing either connector to be used (but not both at the same time). And I have matched his pin-out as well. I thought this was a great idea, and it gives us a solution that should work for everyone. Please note that pin-12 of the SIO Jack does connect to Pin-7 of the D-Sub15M, but has no other connection (this was originally designated as +12 VDC on the 400/800, which was dropped on the XL/XE series).

 

Since I have chosen to use a male D-Sub connector on my project, and the SDrive uses a female, a D-Sub 15 Male-to-Female cable would connect an SDrive to my motherboard. BTW, that adapter cable shown is to convert the SDrive's D-Sub connector to a standard Atari SIO plug (not exactly the same situation as my usage on the 1088XEL motherboard side, which would require the opposite sex).

 

Updated Schematic: Attached File  1088XEL_V1_X_1-18-2017_schema.pdf   244.39KB   76 downloads

 

- Michael


Edited by mytekcontrols, Thu Jan 19, 2017 2:20 AM.


#53 bob1200xl OFFLINE  

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Posted Thu Jan 19, 2017 12:24 PM

I started to meter out the Atari cable that converts SIO to DB-15, but they must have been a little loopy that day (!). The pin assignments appear to be random... 2 goes to 7, 3 goes to 5, 4 goes to 1 - like that.

 

No value here.

 

Bob



#54 mytekcontrols OFFLINE  

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Posted Thu Jan 19, 2017 1:13 PM

I started to meter out the Atari cable that converts SIO to DB-15, but they must have been a little loopy that day (!). The pin assignments appear to be random... 2 goes to 7, 3 goes to 5, 4 goes to 1 - like that.

 

No value here.

 

Bob

 

Maybe that was one of those smoking the green stuff days  ;)

 

Thanks for checking it out, but yes I would agree that there is no value to what they did, especially considering the rarity of that particular printer. And it just makes sense to support the pin-out shown below that apparently was established back in 2007, or possibly even earlier (same as used on both the old and the new version of SDrive).

 

dsub15m.gif

 

Link to website (use google translate)

 

And at one time there were several SIO devices made to use this standard...

 

siodevices.jpg

 

A sampling of some SIO devices with D-SUB15F connector.
From the left: (1) SIO "splitter" (2) SIO special switch for SIO2PC and Multilink,
(3) SIO2PC, (4) Multilink

 

- Michael


Edited by mytekcontrols, Thu Jan 19, 2017 1:26 PM.


#55 mytekcontrols OFFLINE  

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Posted Thu Jan 19, 2017 2:48 PM

Updated Schematic (V1.X 1/19/2017): Attached File  1088XEL_V1_X_1-19-2017_schema.pdf   252.58KB   70 downloads

Changes

  1. Finished audio section, and opted for a future connection point for possible stereo audio-in from the PBI (3-terminal header, using jumper block to route PBI audio-in to both the right and left channel outputs)
  2. Two PBI connectors will now be supported, one meant for internal expansion (within the enclosure), and the 2nd for external connection (outside of the enclosure).

 

After thinking long and hard, I decided it was best to not include any mux/demux one-wire stereo PBI audio-input scheme in the 1088XEL, but instead to allow a future connection for this purpose if it ever materializes. The multiplex aspect would be fairly easy to support on the PBI Device, consisting of a divide x N counter and a dual analog switch. But on the de-multiplexer side it gets a bit more involved, requiring the same counter and analog switch, but also a dual high speed sample & hold amplifier stage. The idea being to clock the counters on both the mux and demux sides with the PH2 signal, and have the counter resets tied to RST to bring them into sync. The counters would then flip/flop between the analog switches feeding and extracting the left and right audio into a common single wire connected to a stereo PBI Device. Unfortunately my research has been to no avail in finding an integrated stereo mux/demux chip, which would make things so much simpler, or a reasonably priced high speed sample & hold amplifier. Other options such as utilizing simple to implement FM stereo transmitter/receiver combination also hasn't yielded an inexpensive compact solution. Not saying that something isn't out there, but I just haven't found it. So not wanting to hold things up on such a minor and perhaps never used aspect, I'm moving on without it.

 

Because people have mentioned wanting to put stuff like a hard drive inside the same case as the motherboard, I thought why not provide an additional PBI connection for possibly doing so, hence the inclusion of an 'internal' PBI connector. Of course both the internal and externally connected devices would need to cooperate with each other since they are sharing the bus, but that was the original idea behind the PBI routines in the OS.

- Michael


Edited by mytekcontrols, Thu Jan 19, 2017 2:56 PM.


#56 ivop OFFLINE  

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Posted Thu Jan 19, 2017 3:00 PM

Perhaps AtariAge user 'analmux' has more knowledge abhout how to mux and demux analog signals in an efficient way, assuming he chose his username ANALog MUXer because he is fond of ehm.. analog muxing :)



#57 BillC OFFLINE  

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Posted Thu Jan 19, 2017 6:04 PM

Michael: The pin numbering of the DA15 connector reverses when changing gender(as does the SIO), if you use the correct gender in the schematic the software should automatically route the traces to the appropriate pads.



#58 mytekcontrols OFFLINE  

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Posted Fri Jan 20, 2017 12:38 AM

Michael: The pin numbering of the DA15 connector reverses when changing gender(as does the SIO), if you use the correct gender in the schematic the software should automatically route the traces to the appropriate pads.

 

Well that kind of depends upon how you look at it. If I view a male DA-15 connector straight on from the connection side (with the solder side on the back, and out of my view) it looks like this...

 

DA-15_DSubM.png

 

Then if I plug a female into that, and continue to look at it from this viewpoint, I will see the solder side of the female connector having the same pin-out with pin-9 to the left and pin-15 to the right. And obviously if I disconnect the female and then turn it around so that it now has it's connection side facing me, the pin numbers will reverse with pin-15 being on the left and pin-9 on the right. Bottom line is that no matter how you view it, when the male and female are plugged together their numbers will always match.

 

And here is my proposed dual connector SIO/DA-15M trace connectios to each other...

 

6YTPKz8.png

And here is the original specification for this alternative SIO connector...

 

dsub15m.gif

 

 

So far I see no problem with how I showed this on my schematic  :?   And even if I did mirror something, which I don't believe I did, as you said it doesn't matter so long as the pin number connections match (which they do). Am I missing something?

 

But thanks for the concern, and also thanks once again for pointing me in this direction in the first place  :)

 

- Michael



#59 mytekcontrols OFFLINE  

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Posted Fri Jan 20, 2017 12:50 PM

Updated Schematic (V1.X 1/20/2017): Attached File  1088XEL_V1_X_1-20-2017_schema.pdf   258.16KB   63 downloads

 

Changes

  1. SIO2PC-USB F232RL Breakout Board correction --- removed +5 VDC connection (power is derived from USB).
  2. Added Expansion Port header for future Rapidus and VBXE installation, provides needed signals for these upgrades (and breaks out unused HCT138 decoding).

fpf6Sfp.png

Note: the reason for the two /EXTSEL pin assignments, is that both the Rapidus and VBXE upgrades require this signal.

 

So although I won't be integrating a 65816, linear ram, or special graphics processing in my design, I will aim to support recognized add-on's for these features. Did I miss anything?

 

- Michael


Edited by mytekcontrols, Fri Jan 20, 2017 12:53 PM.


#60 Matej OFFLINE  

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Posted Sat Jan 21, 2017 11:08 AM

Beautiful project! I support it. Will be there stereo pokey upgrade? I like mini-ITX idea too!



#61 mytekcontrols OFFLINE  

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Posted Sat Jan 21, 2017 2:26 PM

Beautiful project! I support it. Will be there stereo pokey upgrade? I like mini-ITX idea too!

 

Hi Matej  :)

 

Stereo Pokey is built-in  :grin: , as well as a few other upgrades.

 

- Michael



#62 Blues76 OFFLINE  

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Posted Sat Jan 21, 2017 8:15 PM

I've been hinting that this was in the works for a while now. And I figure its time to start revealing a bit of what I have been working on for the last 1-1/2 years. I call it the 1088XEL. Why? Well for one thing thanks to Lotharek's U1MB board and the on-board 64K RAM, there is a total of 1088K of usable memory. Basically the idea behind this project is to create something that is designed from the ground up to accept some of the most popular upgrades as plug-in daughter boards. Yes no more making up wire harnesses, crimping terminals, scratching your head and trying to figure out where to mount things.

 

The other goal of the project is create a very small footprint mother board. I'm talking about something in the area of 6" x 6" (15x15 centimeters). And to utilize only thru-hole components, as well as the original five A8 LSI chips (Sally, Antic, GTIA, Pokey, PIA). Actually there will be an additional Pokey on board to support Stereo Sound. If you've been following some of my other projects, then you've witnessed the nesting technique I wish to exploit when laying out this board, which is how I will get it shrunk down to such a small size without resorting to surface mount devices.

 

The first prototype will initially be created as an NTSC version board, but will provide support for an upgrade path to PAL via a future daughter board design, an oscillator change, and of course PAL Antic and GTIA chips.

 

I have taken some liberties at reducing the component count by eliminating capacitors, some support chips (through utilization of SRAM memory), and just not caring too much about RFI radiation issues. Me bad  :spidey:

 

So for all intents and purposes this will still be a 'real' Atari 8-bit computer as far as the basic hardware is concerned (not an FPGA implementation).

 

Now for the big reveal (please keep in mind that these are preliminary schematics, and that the design is still in flux, so in other words there might be a few mistakes and omissions ;) )...

 

 

 

- Michael

 

 

Michael, 

 

Do you think this is a project that may be ready in 2018 or before? 

 

What a great project!. 



#63 mytekcontrols OFFLINE  

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Posted Sat Jan 21, 2017 9:32 PM

Michael, 

 

Do you think this is a project that may be ready in 2018 or before? 

 

What a great project!. 

 

Thank you :) 

 

I am shooting for the first prototype to be built this year, hopefully before Summer. I hate to have projects drag on forever, and thereby only take on what I plan to make into reality within a relatively short time frame. I assure you, this motherboard project will actually happen  :grin:

 

Presently I'm just doing the final stages of cleaning up the design, and based on feedback by people reading this topic, adding a few extra features that make sense to incorporate. Once this schematic is finished then I'll move on to laying out the PCB. And then... I think you can guess what comes after that  ;)

 

- Michael


Edited by mytekcontrols, Sat Jan 21, 2017 9:33 PM.


#64 Kyle22 OFFLINE  

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Posted Sat Jan 21, 2017 9:52 PM

Just an idea... How about make this look like a 1450XLD?



#65 mytekcontrols OFFLINE  

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Posted Sat Jan 21, 2017 10:20 PM

Just an idea... How about make this look like a 1450XLD?

 

In what way?

 

- Michael



#66 Kyle22 OFFLINE  

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Posted Sun Jan 22, 2017 12:21 AM

 

In what way?

 

- Michael

If anyone wanted to make a case for it.

3D Print, whatever...



#67 mytekcontrols OFFLINE  

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Posted Sun Jan 22, 2017 1:35 AM

Just an idea... How about make this look like a 1450XLD?

 

If anyone wanted to make a case for it.
3D Print, whatever...


Although an intriguing idea, and not out of the realm of possibility for yet another iteration of what I am intending to do on the first run, I have my heart set on doing this in a Mini-ITX form factor which I thought was a fantastic idea proposed by TXG/MNX. I know it won't have that Atari feel to it, but at least there are a multitude of enclosures in all shapes, sizes, styles, and colors that will work with this form factor, and they are ready for purchase like... right now instantly.

 

Also Kyle (and a few others) please keep in mind that I have my own vision of what I what this to be, and that vision just isn't the same as Atari's. Not saying they did anything wrong, or that I don't like what they created, but why would I go through all this trouble to simply recreate what they already accomplished over 30 years ago? No this project is about being unique and not the same old tech that can be purchased on eBay almost any day of the week. Do I expect you or anyone else to agree with my choices and/or direction? No I don't.

 

It's really quite interesting too, that every attempt that has been made over the years to create a new Atari 8-bit MOBO has consistently failed to materialize. Oh there's been a lot of talk, and a lot of ideas tossed around on how this should be done, but not even one of those discussions ever saw the beginnings of any new documentation come out of it (schematics, block diagrams, ect.). But boy let me tell you there were a lot of opinions of how it should be done, and a bazillion things people wanted it to do. But at the end of the day was there anything to show for it? No.

 

Someone on this topic already said something to the effect of "Why reinvent the wheel..let's get serious...". I didn't really reply to that at the time, but I will now. I think I have certainly demonstrated how serious I am, and that I am not simply trying to re-invent the wheel with this project. If I were doing that, I would just make a direct copy of one of the Atari boards and be done with it. Or why the hell kill myself, I'll just grab a Pi, load in an emulator and be finished by this evening. Or how about slap in an FPGA and load up one of the A8 cores. No I'm not going to do that because this isn't what this project was about. And I'm also not saying that any of those other ideas aren't good either.. there just different than what I want to do. I underlined that last part because it best defines the criteria behind this project.

 

Now does that mean I'm closed to new ideas? No. In fact several of the ideas put forth I have been actively trying to incorporate (i.e., Mini-ITX Form Factor, DA-15 SIO to follow already established standard, lay out the board to use both a DA-15 and the original SIO jack, add features that will allow better/easier integration with VBXE and Rapidus). But at the end of the day since this is my project (which is a non-profit effort by the way), I reserve the right to make it how I see fit. So the reason I am saying all of this, is not to piss anyone off or to confirm what an A__hole I am, but to give people a better sense of why I even started this topic and what the project is all about. Of course people may actually agree that I am an A__hole, but that's OK too  :grin:

 

Best regards,

- Michael

 

EDIT:   BTW, I'm not picking on you Kyle, you just reminded me of something I wanted to say for a while now. And I really do think your idea has merit also, but unfortunately it just doesn't fit into what i want to do on this go around  :)


Edited by mytekcontrols, Sun Jan 22, 2017 1:39 AM.


#68 Sugarland OFFLINE  

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Posted Sun Jan 22, 2017 3:24 AM

mytekcontrols, I agree with that stance. You've said up front it's a motherboard project. What makes a 1450XLD so exciting is much more the case than the motherboard.  I'd love to see a 1450XL(D) case project but this is very different.

 

I'm interested in your progress and a final release! Thank you for doing this.



#69 mytekcontrols OFFLINE  

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Posted Sun Jan 22, 2017 9:47 AM

mytekcontrols, I agree with that stance. You've said up front it's a motherboard project. What makes a 1450XLD so exciting is much more the case than the motherboard.  I'd love to see a 1450XL(D) case project but this is very different.
 
I'm interested in your progress and a final release! Thank you for doing this.


You get where I'm coming from, thank you. Yes a new case patterned after that series would be fantastic, but that is a subject for an entirely different thread, and it deserves its own unique topic be started to cover it. Here we're all about the creation of a new and unique A8 motherboard still based on actual Atari LSI chips, but there is where the similarity ends. It should be 100% software compatible, and right out of the box it will have stereo sound, the best standard video (thanks to Bryan's UAV board), a PS2 keyboard and mouse, and all of the great features of the U1MB via an easy no ribbon cable, no wiring, plug and go interface. There's more, but that'll get covered as I go.

- Michael

#70 Bikerbob OFFLINE  

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Posted Sun Jan 22, 2017 11:53 AM

To tag on to that thought Michael, I am reading this with much interest, as I think this might be something I would really enjoy. (Your MB project)

 

But it has been a goal of mine to have a modern i5 or whatever in a GOOD LOOKING atari type case as well.. So that I could do my modern tasks with a awesome retro feel.

 

At the moment I am trying to stuff mini ITX etc into a 800xl or 800 case (just in the planning stages) but I dont want to hack it up at all.

 

If in another thread etc.. a project to make a 1450xld looking case.. but have a modern keyboard in it, so we could mount a itx based Q87 or something MB would be amazing. XEGS is about the best idea for this.. but its just not retro enough for me.. I would like an AIO case that just looks 1984.

 

I would love to have someone LOOK at my space and say?? just Atari computers?? muhahaha ;)



#71 lemiel OFFLINE  

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Posted Sun Jan 22, 2017 11:53 AM

Why no Covox?
I know that it is no to much popular.

#72 mytekcontrols OFFLINE  

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Posted Sun Jan 22, 2017 12:01 PM

Why no Covox?
I know that it is no to much popular.

 

Hi Lemiel  :)

 

You kind of answered your own question, and I agree, not so popular and not well supported by applications. Of course it's the old "which came first: the chicken or the egg?" story. If you don't first have the egg (the Covox device), then how will you ever get the chicken (the software support). So let's say I did want to include a Covox, what would be the best approach to use? What makes the most sense? Any suggestions?

 

- Michael



#73 Kavik OFFLINE  

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Posted Sun Jan 22, 2017 2:21 PM

You get where I'm coming from, thank you. Yes a new case patterned after that series would be fantastic, but that is a subject for an entirely different thread, and it deserves its own unique topic be started to cover it. Here we're all about the creation of a new and unique A8 motherboard still based on actual Atari LSI chips, but there is where the similarity ends. It should be 100% software compatible, and right out of the box it will have stereo sound, the best standard video (thanks to Bryan's UAV board), a PS2 keyboard and mouse, and all of the great features of the U1MB via an easy no ribbon cable, no wiring, plug and go interface. There's more, but that'll get covered as I go.

- Michael

 

I'm very interested and looking forward to supporting this project.  I've been very jealous of the C64 Reloaded motherboard, so this is like a dream come true.  :grin:

 

Any thoughts on how the daughterboards or modularity would work in terms of the form factor?



#74 mytekcontrols OFFLINE  

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Posted Mon Jan 23, 2017 1:24 AM

I'm very interested and looking forward to supporting this project.  I've been very jealous of the C64 Reloaded motherboard, so this is like a dream come true.  :grin:

 

Any thoughts on how the daughterboards or modularity would work in terms of the form factor?

 

Hi Kavik  :)

 

I just started to play around with the layout, and although it's still far, far from complete (only been working on it for about a day now), it might give you a basic idea of where I'm heading.

 

VH6G8rG.png

 

Off to the right side can be seen all of the IC chips that will eventually need to reside on this board. And inside the board footprint I have shown a U1MB being treated as a plug-in module (will require vertical headers in place of the right angle ones it normally comes with). So basically anyplace inside the U1MB footprint that isn't occupied by a header, is fair game for other components that don't stick up very high, such as an IC chip. This is how I'll be able to fit all of the required components within the Mini-ITX Form factor, while still allowing for 3rd party upgrades such as the U1MB, UAV, Rapidus, VBXE, and Sophia. And other upgrades that I have design rights to such as TK-II-Stereo, MOUSETARI, and V-Gate will be integrated into the board.

 

The EUI (Enhanced Upgrade Interface) simply breaks out signals required by some of those 3rd party upgrades.

 

I'm also toying around with the idea of providing up to two internal PBI ports for low profile PBI Devices such as perhaps an IDE card or some other useful piece of hardware that can benefit from a parallel interface.

 

And yes there will be a cartridge port as well, but I haven't made the component for it yet.

 

- Michael


Edited by mytekcontrols, Mon Jan 23, 2017 1:46 AM.


#75 BillC OFFLINE  

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Posted Mon Jan 23, 2017 2:53 AM

The cartridge port is simply a 30-pin card edge connector.

 

These appear to be similar to the type used in the 600XL/800XL, I'm not cetain about PCB thisckness though.

There should also be a provision to open the bottom door on the original brown Atari cartridges. This could be done by using the plastic piece used in the 600XL/800XL,  or some other method.

 

http://www.mouser.co...JAEyt9grmD5ww==

eBay Auction -- Item Number: 130805266999

eBay Auction -- Item Number: 122111327878 w/mounting ears

 







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