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1088XEL Alternative Mother-Board Project

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So you need the U1MB for any OS?

The U1MB works with any OS, and any (or no) DOS.

 

Edit: I should add that the U1MB is required for operation.

Edited by Kyle22
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So you need the U1MB for any OS?

The 1088XEL design is based on having the U1MB as an integral component. It serves up the OS, the built-in language (Basic), and the ram expansion beyond the 64k base. It obviously does much more than this, but the first item I mentioned is essential, since without an OS not much is going to happen. As to what that OS will be, is entirely up to you.

 

I took this approach since to do all the things that the U1MB is capable of with a discrete design would have been rather involved and likely not saved much money in the long run. It also would not have been practical with a thru-hole approach, which was a major goal of this project.

 

- Michael

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Yet another Schematic Update: 1088XEL_V1_X_2-20-2017_schema.pdf

 

Changes...

 

  1. Dual XL PBI slots removed.
  2. Implemented Single Slot Parallel Interface based on 130XE Cart/ECI, and as such will now use edge card connectors allowing compatibility with 130XE style expansion boards. Only exception: implemented as internal only version of such. This feature best utilized in larger Mini-ITX enclosures that provide for extra height and PCI rear bracket usage, where external access would be available to the expansion card for plugging in stuff (depending upon expansion device requirements, may require some customization and/or extension).
  3. Unused reserved pin of ECI designated as Right Channel Audio input, enabling a stereo specific expansion board to utilize the 1088XEL's on-board stereo audio circuits and Stereo/Mono switching via the U1MB Set-up Menu (this enabled elimination of Stereo DEMUX port, and associated circuitry).
  4. Audio Stereo/Mono switching now utilizing 74HCT4053 triple dual-channel analog switch instead of former 74HCT4066 chip.
  5. Audio mixing circuit has undergone component reduction by utilization of larger resistor array networks.
  6. Momentary push button power switch circuit now has blocking diode (circuit operation still needs to be verified, so other changes might be in order). Also will eventually add power switching of PC type PSU where extra voltages (+12 VDC) are required, otherwise board will run directly from cell phone type charger with suitable adapter cord.
  7. 2nd Pokey IRQ is tied into common interrupt input, but also has enable/disable feature provided by U1MB Setup Menu using available output connection.

 

Announcement...

 

Due to some feedback I received, I feel that it is important that I point out the following. Some of this is simple reiteration of what I have already said.

 

This project started out life as something I wanted to do for myself, with no intention of ever selling it. This topic was and still is about sharing the journey of what I intend to do in this regard. So it should go without saying that this is not a commercial venture, and as such may fall short of expectations of what people ultimately want. So if this isn't your cup of tea, I fully understand. With that said I am hoping to benefit from peoples suggestions and ideas to make this project even better. However please keep in mind that I reserve the right to make this about my dream, and not necessarily yours.

 

As can be seen I will be releasing documentation through out the design process, culminating in an open source package release by the end of the project. That package will contain the schematic and PCB work files in ExpressPCB format, as well as a PCB design file in Robot Room's Copper Connection proprietary file format for purposes of implementing special text and logo silkscreen artwork that isn't possible in the ExpressPCB software. The ExpressPCB software is free, however it doesn't have Gerber export capability. For that I also use Copper Connection which isn't free (Gerber export is provided starting in the Studio version which costs $49). However for purposes of exactly duplicating my PCB design, the open source package release will also include the Gerber files generated by Copper Connection, which will allow you to have boards made anywhere. But if you decide to modify this project more to your liking, you will need to purchase either Copper Connection or utilize a conversion service if you don't want to have boards made by ExpressPCB which will be extremely expensive, since this is a 4-layer board.

 

This project falls under a Creative Commons Attribution-ShareAlike 4.0 International License 88x31.png

 

I hope you are all enjoying this journey with me ;-)

 

- Michael

Edited by mytekcontrols
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I found a very cool looking Mini-ITX case that also presented another possibility to me (see below).

 

KaN2Bo0.png

 

Notice the additional three DB-9 connector holes :ponder: :idea:

 

So I got to thinking, maybe if I removed the stacked DB-9's on my design, opted for a dual row IDC ribbon header for each on my board, and then had some short ribbon cables terminated with DB-9's routed to these (or similar) com port cut-outs, guess what... I'd have room for a real SIO jack once again on my 1088XEL :-D . And with one more DB-9 port left over, a Sophia DB-9 RGB or VBXE VGA connector would also be possible (in addition to the DIN 13 RGB connection, which I'll be keeping).

 

Here's a look at that case assembled...

 

2jrSRFK.png

 

It comes with a USB connector and cable for the single side entry hole. Don't have an immediate use for this, but perhaps with a down the road upgrade something might be able to take advantage of this (wireless USB mouse comes to mind).

 

Realan H80 Mini-ITX Gaming Case

 

- Michael

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Another Schematic Update: 1088XEL_V1_X_2-26-2017_schema.pdf


And a revised PCB Layout to go with it...
v8HxgfL.png

Getting ever closer to routing traces, but I do believe I now have all the components placed on the board. And I still do have some circuits to double check for correct functionality.

The PSU aspect has undergone some major design changes to allow the board to run off the standby power (+5VSB) which is normally rated for +5VDC at 2 Amps (more than sufficient for our needs), and will kick on main power when momentarily pressing the power button. If you have no need for +12VDC, then the Mini-ITX or ATX supply can be eliminated, being replaced by a cell phone charger. When using a standard PSU, it will be necessary to adapt the power connector to suit your needs since putting the mating connector on my board was not an option (would have taken considerable real estate and having 30 amps on-board is unsafe). Only requires 3 conections from the PSU to my board (connector shown in upper left corner above).

connector_atx_pinout.GIF


And unless I'm mistaken, I do believe I left enough space around the primary Pokey (Pokey-L) for one of these...

post-26134-0-64783400-1387579989.jpg

post-26134-0-24766000-1387580004.jpg

http://atariage.com/forums/topic/217503-new-hardware-sio-fifo/


- Michael

Edited by mytekcontrols
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Yet Another Update (includes PCB Component Layout and ID): 1088XEL_V1_0_2-28-2017_schema.pdf

 

 

I tentatively have this one labeled as Rev 1.0, since every component has been ID'ed on both the schematic and the PCB, as well as checked for net list errors. Basically this means it's a go on routing the traces, assuming nothing pops up in my mind in the next few days that points to an issue.

 

- Michael

 

 

EDIT: Changed to SparkFun's BOB-12731 FT232RL Break-Out board for the SIO2PC-USB aspect in place of my original choice that was not as readily available, and also cost more. The SparkFun board is carried by various vendors and seems quite popular, and its smaller size is a bonus for me.

Edited by mytekcontrols
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Minor Update: 1088XEL_V1_0_3-01-2017_schema.pdf

 

  • Changed Cart and ECI to proper Edge Card Connectors and realigned into correct position on the board
  • Linked two components from Schematic to Board that were previously unassigned on page 1
  • Moved some components that were close to U1MB connectors in order to provide for box headers
  • Relabeled D1xx-D7xx to /D1xx-/D7xx to appropriately show that signal is active when LOW

Version is still 1.0, but the date has been changed to reflect that this is a newer release.

 

The EUI (Enhanced Upgrade Interface) connector has grown somewhat in the number of signals that are provided. In it's present form it serves as a useful tie in point for the extra signals that Rapidus and VBXE need, as well as providing some future expandabilty by utilization of the /D6xx and /D7xx chip select lines. When combined with the provided A0-A7address, D0-D7data, buffered Phi2 and R/W signals, it becomes a simple parallel interface. This can be used for various DIY projects, whereas the Cart/ECI would be better for a serious parallel bus device.

 

- Michael

 

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I'm dreaming of the day when someone builds a version of your magnificent creation that I can buy.

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I'm dreaming of the day when someone builds a version of your magnificent creation that I can buy.

 

Well if all goes as I have it scheduled, the final tested board designs should be released by the end of Spring. At that point anyone can build one. However due to the 4-layer board, and it being a bit bigger than my previous projects, it won't be a good candidate for OSH Park, and thereby needs to be fabricated by an alternative PCB supplier. So this probably means a minimum order of 5 boards, which will be a bit pricey if all you want is one board. But all is not lost, since I have been talking with at least one guy that has in the past built up some of these DIY projects, and I strongly suspect he'll be doing some of these to sell. There will likely be a few others doing the same, and hopefully located in other countries to keep the shipping more reasonable.

 

I on the other hand I will not be selling any of these myself, but might give a few unstuffed boards out to my beta testers to get things rolling. And of course I will be building a few complete systems for myself, because after all that was the original idea behind this project :grin: I would also love to bring some of these to demo at this years Atari Party 2017 if that will be happening once again in Davis CA or close enough that it's within easy travel for me. Should be fun!

 

Thank you for your interest :)

 

- Michael

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For those state side interested in a board (s), we can organize a group purchase to reduce the cost per board. One trusted person would collect funds, place order, receive said boards, pack & ship board(s) to group members who bought in. In the end we save money on boards and shipping.

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For those state side interested in a board (s), we can organize a group purchase to reduce the cost per board. One trusted person would collect funds, place order, receive said boards, pack & ship board(s) to group members who bought in. In the end we save money on boards and shipping.

I'd be up for purchasing a board that way.

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For those state side interested in a board (s), we can organize a group purchase to reduce the cost per board. One trusted person would collect funds, place order, receive said boards, pack & ship board(s) to group members who bought in. In the end we save money on boards and shipping.

 

That sounds like a great idea :)

 

I also have my fingers crossed on the safe arrival of a box containing several hundred NOS SIO board style connectors through an old acquaintance of mine (a blast from the past) who was digging out stuff from an old storage and discovered them. Hence the reason I decided to do what was necessary to reinstate the 'stock' connector on my board. I'm getting these for free, but have decided to let someone else handle the distribution of these to needy individuals. I don't want to jinx it, so I'll hold off on saying who that is until this becomes a reality. Suffice it to say this individual doesn't live very far from me (2 hour drive), so we'll be handing the box off face to face. He will likely also be a source for an assembled version of the 1088XEL.

 

- Michael

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count me in

Hi ndary,

 

It's good to know that there is interest in this project, but I don't want this topic to become a pre-order thread since I won't be the one building these. So let's assume that when the time does come for doing so, that a separate 'order' topic will be created for this. BTW, I know you and Bob attended the Atari Party last year, are you planning on doing the same this year? Be great to meet you in person.

 

- Michael

 

EDIT: Anyone know of when this year's Atari Party event will be?

Edited by mytekcontrols
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I only commented concerning a possible group purchase on boards so that folks would not get disinterested because they believe the cost for the boards would be too high. These discussions can take life in another thread once Michael has green lighted this project ready for prime time;--) I would also add a group buy on components to can be done. I was part of the Amiga GB1000 board project on two different occasion and the project was only doable because of everybody working together. I add this only for future discussions in future thread, and leave this thread for Michael to share his development progress:--).

 

Mike

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I only commented concerning a possible group purchase on boards so that folks would not get disinterested because they believe the cost for the boards would be too high. These discussions can take life in another thread once Michael has green lighted this project ready for prime time;--) I would also add a group buy on components to can be done. I was part of the Amiga GB1000 board project on two different occasion and the project was only doable because of everybody working together. I add this only for future discussions in future thread, and leave this thread for Michael to share his development progress:--).

 

Mike

 

Sounds like a great plan Firedawg :thumbsup: :)

 

My previous comment was just to make sure that people didn't assume that this topic was turning into a pre-order thread (which it isn't). But I really like the idea that you have proposed, since this will require a lot more parts than your normal DIY upgrade, and doing a group buy can likely make a big cost difference. When the time is right I will be sure to raise that green flag (or turn on the green light) to signify that all is a GO ;)

 

Thank you,

 

- Michael

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Bill is moving to Washington (whaaaaaaaa...) this summer so I doubt we will have an Atari Party this year.

 

Bob

 

 

Hi ndary,

It's good to know that there is interest in this project, but I don't want this topic to become a pre-order thread since I won't be the one building these. So let's assume that when the time does come for doing so, that a separate 'order' topic will be created for this. BTW, I know you and Bob attended the Atari Party last year, are you planning on doing the same this year? Be great to meet you in person.

- Michael

EDIT: Anyone know of when this year's Atari Party event will be?

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Bill is moving to Washington (whaaaaaaaa...) this summer so I doubt we will have an Atari Party this year.

 

Bob

 

 

 

That makes me very sad :_(

 

I knew I should have went with you last year (stupid me). I'm not much for traveling, so what and where is the next event that would have A8 attendees?

 

- Michael

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I got my new Mini-ITX case yesterday (very fast shipping), and I started to play around with it. It came with two LED's built into the power switch (red and blue). The red was intended to be an HDD activity light, but I think it'll work great for the SIO2PC activity instead. It's actually a very nice case, and not something that could have easily been done in a DIY fashion, especially not for the price (Realan H80 Mini-ITX Gaming Case).

 

p2Mlj5T.jpg

 

 

So I was looking at the cartridge situation, and decided that this would be a good application for a custom top panel to take the place of the original one that came with the case. So I whipped out the Front Panel Express Designer software and created this (the lettering will be engraved into the black anodized aluminum revealing the silver color underneath).

 

hkAKYPM.png

 

And I'm also toying around with making a custom bezel plate for the back that will have similar (but much smaller) lettering to identify all of the ports. Should look real sweet.

 

Note: For my personal system, I don't require the ECI port. So simply providing the cart opening for the SIDE2 really does it quite nicely for me.

 

Working with this case has turned into a good exercise to really check out the fit and positioning of stuff on the board before it gets totally locked in, and I ended up moving a few items around to make more space around the cartridge because of it. Still not enough to use a conventional cart guide as used in the XL series, but enough to use a custom 3D printed one of some kind. Speaking of which, that is one thing I can't presently do, so I'll be looking for someone that's familiar with 3D printing technology to create something appropriate. Obviously it'll not be needed for many of the non-Atari carts, but occasionally I do like to use those. Nothing fancy really required, probably just something that slips over the edge card connector with the cart door release fingers, and attached with glue to the connector.

 

Here's a look at where I'm presently at with the PCB component placement...

 

mvWtYXT.png

 

And a 'to scale' drawing of the front and back side: 1088XEL Rev1_0 Component Placement 3-2-2017.pdf

 

And it goes without saying, any files that are generated for any of the custom parts will be a included into the final project release. So if you want to use that custom top panel, you'll have the file for it. And that can used to place an order for one with Front Panel Express, and/or modify it to your liking with their free software.

 

- Michael

Edited by mytekcontrols
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Michael, I believe you just hit it out of the park on that one.

 

Home run as far as I am concerned. Absolutely beautiful 😃

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Michael, I believe you just hit it out of the park on that one.

 

Home run as far as I am concerned. Absolutely beautiful

 

Thanks Kyle :)

 

Yeah it's definitely going in a good direction for sure. And I think the coolest part about this project, will be to see all the different ways people will eventually package it.

 

- Michael

 

EDIT: I just found a couple of boo boo's on the color oscillator (accidentally inverted the transistors). So expect another full update soon.

1088XEL_V1_0_3-02-2017_schema.pdf

Edited by mytekcontrols

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It's a very cool project Michael and interesting to watch as it develops.

 

One thing about the cart slot, do you have some plan for protecting the cartridge plastic from the aluminum edge? For someone who continually uses a single cart, I'm sure it wouldn't be an issue; but for someone constantly switching between carts -- especially those that may have value based on condition -- it might present a slightly unnerving situation.

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It's a very cool project Michael and interesting to watch as it develops.

 

One thing about the cart slot, do you have some plan for protecting the cartridge plastic from the aluminum edge? For someone who continually uses a single cart, I'm sure it wouldn't be an issue; but for someone constantly switching between carts -- especially those that may have value based on condition -- it might present a slightly unnerving situation.

 

That is a good point. Maybe a 3d printed ABS tunnel might be the ticket, something with a flange-over on the top where a dab of adhesive would hold it in place. Could even be integrated with the cart door fingers perhaps (kind of like what the 1200XL had, but made a bit wider). Definitely something to think about and consider. Good thing is I still have time before that decision is needed. In the meantime I need to route traces, do a proto run, stuff and solder, and then test, test, test. I'll be busy for the next couple of months with that alone. However I'll try to get something drawn up and posted here for further thought.

 

Thanks for pointing that out :)

 

----------------------------------------------

 

I guess that update did get uploaded on my previous post (I got booted out when editing the post before I could write what it was all about). Correction, I just tried to open that attached file and it says I don't have permission to do so. Anyway here is a new upload of that file and a description of what got changed...

 

1088XEL_V1_0_3-02-2017_schema.pdf

 

(Reference Page 2) Following a test of the originally proposed primary crystal oscillator circuit, it was discovered that my reduced component count version was not going to work properly (this decision came even after correcting for the inverted emitter-collector arrangement). So I updated it to use the same setup as the 800XL, which works fine, but did require two additional resistors as compared to the previous circuit. I guess those Atari Engineers knew what they were doing, and me not so much, at least when it comes to transistor oscillator circuit design ;-) .

 

 

- Michael

Edited by mytekcontrols

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That is a good point. Maybe a 3d printed ABS tunnel might be the ticket, something with a flange-over on the top where a dab of adhesive would hold it in place. Could even be integrated with the cart door fingers perhaps (kind of like what the 1200XL had, but made a bit wider). Definitely something to think about and consider. Good thing is I still have time before that decision is needed. In the meantime I need to route traces, do a proto run, stuff and solder, and then test, test, test. I'll be busy for the next couple of months with that alone. However I'll try to get something drawn up and posted here for further thought.

 

Thanks for pointing that out :)

 

----------------------------------------------

 

I guess that update did get uploaded on my previous post (I got booted out when editing the post before I could write what it was all about). Correction, I just tried to open that attached file and it says I don't have permission to do so. Anyway here is a new upload of that file and a description of what got changed...

 

attachicon.gif1088XEL_V1_0_3-02-2017_schema.pdf

 

(Reference Page 2) Following a test of the originally proposed primary crystal oscillator circuit, it was discovered that my reduced component count version was not going to work properly (this decision came even after correcting for the inverted emitter-collector arrangement). So I updated it to use the same setup as the 800XL, which works fine, but did require two additional resistors as compared to the previous circuit. I guess those Atari Engineers knew what they were doing, and me not so much, at least when it comes to transistor oscillator circuit design ;-) .

 

 

- Michael

A 90 degree connector would also help. You should insert the cart from the side. More dust-proof too.

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