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1088 XEL - MyTek -- Your opinion and experience

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53 minutes ago, Levas said:

Hi All,

I have my humble opinion about this device. First of all thanks for interesting project, but the BOM looks crazy. Not special chips, but resistor modules. Who ever are using two different resistor modules with 8 and 7 resistors inside? Just place two identical 4K7*8 resistor set and leave one pin floating! Same with 3K3 4 and 5 resistor sets. At least it is nice, that I can use single resistors in other places. Even SMD ones instead of 100K module. Also, I am not sure if there must be such exact value for digital schematics.

I don't see how it's so crazy to use only what specific SIP resistor arrays are required, especially when there would be no cost savings to go the route you propose (quantity discounts normally only kick in for 10 pieces or more).

 

53 minutes ago, Levas said:

Another think is that I must have specific expensive modules for video, ROM and MMU.

Well first of all the U1MB as a replacement for the standard OS ROM and MMU is worth every penny in this application when you consider how it enables the rather simple IDE/CF interface hardware, adds 1MB of extended memory, can swap up to 4 OS and 4 language ROMs on the fly (8 if configured as XEGS), easy configuration changes, built-in RTC, built in SDX, need I go on?

 

53 minutes ago, Levas said:

It is nice that connector is just mirror image of ROM and PAL/GAL chip.

Well I guess I did something right ;) .

 

53 minutes ago, Levas said:

It works. It is pity, that there is no Eagle files for it. I would like to make some modifications: SMD resistors and general chips. It was much harder to get "generic" chips compared to Atari ones.

The schematic was translated into KiCad I believe - just need to do a search for that, and then have at it.

 

43 minutes ago, orpheuswaking said:

Well thanks for your first post, clearly the 1088XEL isn't for you... 

:lolblue:

 

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1 hour ago, Levas said:

Hi All,

I have my humble opinion about this device. First of all thanks for interesting project, but the BOM looks crazy. Not special chips, but resistor modules. Who ever are using two different resistor modules with 8 and 7 resistors inside? Just place two identical 4K7*8 resistor set and leave one pin floating! Same with 3K3 4 and 5 resistor sets. At least it is nice, that I can use single resistors in other places. Even SMD ones instead of 100K module. Also, I am not sure if there must be such exact value for digital schematics.

Let me show you what you did wrong:

https://getyarn.io/yarn-clip/1976cd59-01f3-4ca2-aa1a-aa092c2ec18d

 

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21 hours ago, mytek said:

I don't see how it's so crazy to use only what specific SIP resistor arrays are required, especially when there would be no cost savings to go the route you propose (quantity discounts normally only kick in for 10 pieces or more).

 

None of bigger component sellers (digikey, mouser) and local sellers have these in stock. :) At least when I was ordering.

7 or 8 resistor (bus type) - 8 resistors are more popular. Meanwhile there is decision- use TWO BOM items or just leave one pin floating. This is no cost saving optimization. Main BOM rule- keep it short.

Some generic 74 chips were out of stock too.

 

21 hours ago, mytek said:

The schematic was translated into KiCad I believe - just need to do a search for that, and then have at it.

 

:lolblue:

 

I am not good at KiCad. :(

 

Thanks for your work. You have true believers on your side. You can start your own Jihad if you need. :)

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1 minute ago, Levas said:

You have true believers on your side. You can start your own Jihad if you need.

No, he has people who have successfully built and used these systems for several years now. In fact, three years ago today I was building my own XEL. 

 

There’s no need to be a dick about it - if you dislike the system, design your own or build something else. 

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21 hours ago, mytek said:

Well first of all the U1MB as a replacement for the standard OS ROM and MMU is worth every penny in this application when you consider how it enables the rather simple IDE/CF interface hardware, adds 1MB of extended memory, can swap up to 4 OS and 4 language ROMs on the fly (8 if configured as XEGS), easy configuration changes, built-in RTC, built in SDX, need I go on?

I suppose @Levas missed that the design was completely build around the U1MB at first.

 

Perhaps the 576NUC+ is more up his alley.

 

Quote

Well I guess I did something right ;) .

Sure :) Like I said before, one could easily create a board that takes standard MMU and ROMS. Edit: with the U1MB footprint and plug it in a 1088XEL. Edit2: Oh, I didn't see his build image yet. Seems like he already did that!

 

Quote

The schematic was translated into KiCad I believe - just need to do a search for that, and then have at it.

https://github.com/ivop/1088xel-kicad

 

I have been contacted privately by at least one person that is considering basing his new design on this KiCad conversion. Proves I have not wasted my time :)

 

 

Edited by ivop
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17 minutes ago, DrVenkman said:

No, he has people who have successfully built and used these systems for several years now. In fact, three years ago today I was building my own XEL. 

 

There’s no need to be a dick about it - if you dislike the system, design your own or build something else. 

I've built it and it works. But there are my opinion about design. And every engineer is happy to know other's opinion. Meanwhile answers- "not for you", "you are wrong" and do not touch our "holly grail" are not very adult.

 

And yes, I am thinking about my own design. But I am not sure where is that thin line between "original" and "modern".

ss20210112_185440.jpg

Edited by Levas
add image

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26 minutes ago, Levas said:

Main BOM rule- keep it short.

Do you have a source for that rule or is it just a personal preference? We could shorten the BOM a great deal by only using 1K resistors and 0.1uf caps.

 

 

14 minutes ago, Levas said:

But there are my opinion about design. And every engineer is happy to know other's opinion.

When your opinion is "This board you built to be an expanded Atari, here's how you could have made it the standard Atari that I want". That's like telling a waffle iron manufacturer that it would make the iron much better at reflow soldering if they had just left out the the small bumps all over the surface.

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42 minutes ago, Levas said:

child talk. Sorry I too old to understand your symbolic language. Please use words if you can.

I'll try to keep it simple for you.

 

Boogie Nights, a smart ass character with a lousy attitude attitude attempts to show what someone did wrong in the pool.  He does the dive and flops hard.  Pretty much like your arrival here.

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Ok let me just say that anyone can criticize my design, after all this is a free country. However I think what got a couple of people worked up is that on your first AtariAge post, and first paragraph of that post you start out by seemingly having an issue with my design and in your words...

 

Quote

...the BOM looks crazy.

But you did say some nice things as well so I'll try to not take offence :) .

 

Looking at your solution to reinstate the original OS ROM and MMU. I also have some suggestions...

 

Alt-XEL.jpg.3f2a63d6b9c9b5c0049ab5d80919d1d5.jpg

 

First of all it looks like a very compact solution you came up with. However it would have been much more solid and stable if you had made a single PCB that spanned both sockets. This would have also facilitated having the chips mounted right side up, thus giving easier access especially to the ROM, which could allow faster swapping for an alternative OS. Speaking of which since you would have extra PCB space available, why not go with an independent socket for the BASIC and the OS ROMs, increase the KB size of each, and have a dip switch or header to select multiple versions of the OS and the Language. You could of also added 512KB of expanded memory by simply adding two more chips as shown HERE.

 

But why cripple the board by not installing a U1MB which would have cost €57.68 ($70.15), have plugged directly in, and given you sooooo much more functionality? It seems like if you don't want that, it would have been far cheaper to just buy a stock Atari 8-bit computer instead of building the 1088XEL. Keep in mind that the whole thrust of this project wasn't just about putting an Atari into a Mini-ITX enclosure, but also having a U1MB as it's heart (something someone else once reminded me about).

 

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5 hours ago, Levas said:

None of bigger component sellers (digikey, mouser) and local sellers have these in stock. :) At least when I was ordering.

 

 

Yes, and this seems a bit odd to me. Of course, I have no idea what they may have had in stock when you tried to source your parts, but when I purchased, I bought 95% of my electronics parts from Digi-Key and had very little trouble getting any of them. Since you were going on about the resistor networks, I just checked, and Digi-Key has a minimum of 750 in stock of every single one of the ones listed on the BOM except for one, and it had a substitute listed at the bottom of the page for that one, and they had almost 1,500 of those in stock. I found all of those just by clicking on the hyperlink in the BOM. How hard did you look? It took me all of maybe five minutes, tops.

 

I'm with the others, you come here, to a long established community, one of the most well respected Atari communities on the Internet, you don't introduce yourself, and your first post is to tell a very hard working and generous member what they did wrong with their work.

 

You may not be a complete jerk, but you definitely exhibit strong jerk-like behavior. I'm sure you're a great guy, but maybe you should think a little before posting next time.

 

Good luck creating a solution that works well for you. As for most of the rest of us, we're thrilled with the 1088XEL & XLD designs as they are.

 

Edited by bfollowell
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@bfollowell thank you for your last post, it is greatly appreciated 👍 . Also thanks for verifying that the parts on the BOM are still available in one form or the other from the quoted vendor. Now days we have to expect some shortages due to the Covid situation, but it's good to see that it isn't drastically so in this case.

 

4 hours ago, ivop said:

https://github.com/ivop/1088xel-kicad

 

I have been contacted privately by at least one person that is considering basing his new design on this KiCad conversion. Proves I have not wasted my time

Thank you @ivop for posting the link to that once again. I really should add that to my 1088XEL webpage at some point. So can you say who is thinking of utilizing this?

 

Unless I am mistaken, @Dropcheck also created some schematics in the Eagle format. If so, it would be nice to have a link to that as well.

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1 hour ago, mytek said:

Thank you @ivop for posting the link to that once again. I really should add that to my 1088XEL webpage at some point. So can you say who is thinking of utilizing this?

It's somebody that contacted me privately. I don't know who he or she is, so I choose to not say who it is, and leave that to the person in question once it results into an actual project :) I have no idea how serious this is.

 

Quote

Unless I am mistaken, @Dropcheck also created some schematics in the Eagle format. If so, it would be nice to have a link to that as well.

I googled it, and lo and behold, it's in the same thread:

 

https://atariage.com/forums/topic/271724-redrawing-the-1088xel-in-kicad/

 

The second last post has @Dropcheck's Eagle version as an attachment :)

Edited by ivop

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1 hour ago, ivop said:

I googled it, and lo and behold, it's in the same thread:

 

https://atariage.com/forums/topic/271724-redrawing-the-1088xel-in-kicad/

 

The second last post has @Dropcheck's Eagle version as an attachment :)

Thanks :) .

 

Just what @Levas was looking for. Well at least the schematics in Eagle. He'll still have to do his own layout from scratch.

 

I added a link to both downloads on my website so people should have a much easier time finding it in the future (https://ataribits.weebly.com/1088xel.html).

 

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1 hour ago, mytek said:

Just what @Levas was looking for. Well at least the schematics in Eagle. He'll still have to do his own layout from scratch.

 

Layout is the most fun part, especially when you are trying to make things as compact as possible while not breaking any PCB design rules. :)

 

@mytek as done an amazing job designed these PCBs and making them very accessible to a spectrum of builders, not just the experts. While I do agree, when making a PCB for mass production, optimizing the BOM is one of the key elements that a developer will go through, to lower the unique part counts (even to select component values based on the overall design), but that doesn't seem to be his goal with the 1088 XEL. I know when I am designing a one-off or something I'm iterating on, I might use parts that I just happen to have on hand, or some other reason, outside of pure part optimization.

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15 hours ago, Mr Robot said:
16 hours ago, Levas said:

Main BOM rule- keep it short.

Do you have a source for that rule or is it just a personal preference? We could shorten the BOM a great deal by only using 1K resistors and 0.1uf caps.

this is industry standard - keep the BOM short, no exceptions here

all the people in a production chain will than you for designing with that rule in mind

 

1088xel is a personal project though - take it or leave it i guess

 

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The diversity of the 1088XEL BOM was in large part required to best mimic the characteristics of the Atari I/O as seen in the later machines. So inputs like the paddle ports required very specific component values in order to work properly, or certain values of pull-up resistors were matched in order to present the same bus loading aspects of the original A8 series machines. However the sheer number of individual components was nearly cut in half by making better choices in circuit design, and introducing newer versions of said components.

 

Yes the possibility existed to perhaps make some of the chosen values more the same across the board, and/or less precise (e.g., 3K instead of 3.3K). But at the end of the day I was way more interested in having something work reliably, than to fuss over the BOM. BTW, anyone can rework the BOM to their own liking if they really wanted to, and were willing to run the verification tests to prove it out.

 

The 1088XEL went from merely an idea to full reality in 9 months. It was released to the public in 2017, with all aspects covered including the source for the PCB layout. Speaking of which, I've heard numerous complaints about the choice made in what program got used for that PCB development. However it was free software that anyone could download, being very easy to learn and use, and never once did I ever experience a lock-up or loss of data, even when running it under Wine for cross platform use under Linux. Sure it doesn't produce gerbers on its own, but several times I mentioned the willingness to do export for anyone that showed me that they were serious. Also I know of at least one online service that will do it for a moderate and reasonable fee. I have yet to see anyone even try. People love to tell you how they would have done it differently, but they rarely ever make the effort to do so themselves.

 

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Thanks for link to Eagle file.

 

Also, I was not able to order both mini DIN connectors. And about Digikey orders, maybe there is some geographical limitations? Anyone from Easter Europe here? Even PAL crystal was out of stock!

 

heresy.thumb.png.62c988f350c195cbb9108593f16e43db.png

First heresy on the board. :)

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30 minutes ago, Levas said:

Even PAL crystal was out of stock!

If you can find a 14.1875 MHz crystal or the equivalent oscillator this could be divided by 4 with 74HCT74 circuit to yield the desired PAL primary frequency of 3.546894 MHz. The 4.433618 MHz (ECS-44-20-4X) PAL Color Burst crystal is readily available from several sources.

 

divideby4.thumb.png.9042bcb00a06fecc65c77e3892ecff69.png

 

 

EDIT: @Levas you should probably start a NEW Topic for what you are working on.

 

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29 minutes ago, Levas said:

heresy.thumb.png.62c988f350c195cbb9108593f16e43db.png

 

First heresy on the board. :)

What a rats nest ;)

 

Are you planing on going full SMD (0812, or smaller?) like the Ultimate C64, but with real Atari custom chips?

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On 1/12/2021 at 8:40 AM, DrVenkman said:

...people who have successfully built and used these systems for several years now. In fact, three years ago today I was building my own XEL...

 

Wow! Has it been 3 years? I ended up building three of these things (2 NTSC 1 PAL) and loving every minute of it. All hail through-hole designs! I think I got all my components from Arrow (they shipped from warehouses all over the world), maybe a few pieces from digikey, and the chips from Best. 

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15 minutes ago, john_q_atari said:

Wow! Has it been 3 years? 

Yeah. I took this photo on January 10, 2018. I was waiting on a couple parts to finish up and my build was paused. I successfully powered it up for the first time on 1/24/2018. 

 

 

DEC2977F-DA76-48FF-B509-1A37C98AD627.jpeg

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i was assembling one to have something i could put in the office without drawing too much attention to it

it took me a while to complete it - for some parts i had to wait two months before they arrived (RAM chip), for others i would still wait if not for good people around here who helped me out (video minidin/rca combination) - even audio jack was not a standard part for me

i quit trying to get every SIP resistor pack so it would look pretty - just went ahead with what i could buy and used that, remaining ones were replaced either by SMD couterpars (100k under POKEY) or with standard THT parts mounted vertically and then soldered with a bar wire

capacitors - i had to ask around, since most of this stuff is phased out and commonly replaced by smt parts

 

crystal choice was also odd for me - it could include that by 4 divider in the first place, since 14.318 or 14.187 crystals are obtainable easy enough, but no - XL part was used

i still doesn't have any sio2pc solution there, or stock video option - uav is no go for me, and sio2pc module is also not possible to buy locally

 

after all this - it didn't work - it appears i was picky about 74ls08 part i was using - fortunatly MOQ was 5, and it had no problem working with another one from that purchase

 

bottom line - it's hard to get assembled on this side of the pond

 

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1 hour ago, candle said:

bottom line - it's hard to get assembled on this side of the pond

Sorry to hear that, although originally it was just a personal project which I had no difficulty getting parts for over here. Later due to many requests I released it for others to build, but do keep in mind that I had little incentive to change things since I don't sell or make money from it (every project I do for the Atari creates another hole in my wallet).

 

1 hour ago, candle said:

it appears i was picky about 74ls08 part i was using

A 74F08 is spec'ed for U13, and a 74HCT08 is spec'ed for U18. Without the faster chip in the U13 socket there will be problems especially when configured for PAL.

 

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