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Gauging interest in a XF551 modified board for 1088XEL


Dropcheck

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Just trying to get a feel for the demand.

 

I've been following Mytekcontrol's amazing 1088XEL project thread over the last few months and wanted to weigh on at least one improvement I have to offer.

I feel one of the few limitations of the 1088XEL project by Mytekcontrols is the case choice which by definition limits the ability to expand. I'm speaking specifically that if you want to use a floppy drive such as the XF551, it's going to be an external device. Candle mentioned some time back in the 1088XEL thread that he preferred to have all his power supply inside the case. I agree, and if we are going to drag kicking and screaming the Atari into the 21st century we should also include the floppy drive inside as well.

To that end I am proposing a modified XF551 mainboard that will fit inside a 3 1/2" drive bay. It will draw power from the SIO port on the 1088XEL board. This modified XF551 mainboard will not need SIO connectors or power supply, It will include circuitry for a track display LED, OS and drive # selection on the front facing bezel. The XF551 compatible floppy drive would fit in a standard 5 1/4" drive bay.

The test mini-itx case I am designing for is this one But others might work just as well. :)

At this time I am leaning towards providing a lean board to keep the costs down, the user will have to provide these items for sure for the board project:

XF551 compatible floppy drive
WD1772 Floppy Drive Chip
Intel 8040/8050 Chip

 

Currently I am working up a BOM and sourcing parts, so I can't say exactly what the cost would be. A wild guess would be around $60 for the board and ATX PS daughter card for the 1088XEL. Maybe less...... I'm going to try to go SMD as much as possible to save just a little more on parts costs.

 

I'll try to get a couple of renderings of what I'm purposing up in this thread in a day or so.

 

At this time I am not planning to offer a 1050 option. For one I don't think a 1050 drive mech will fit inside a standard 5 1/4" drive bay. For another I don't think the 1050 board can be squeezed enough to fit a 3 1/2" drive bay either. Too many parts, too big a drive mech. :(

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This is great news :-D

 

I'll be running some confirmation tests on the 'PSU Control Interface' early next week and post the results here. Basically this interface allows the XEL to switch ON and OFF the PSU's high current and 12V outputs via the same mechanism that switches on it's own main power bus. And the XEL will derive it's power supply from the PSU's standby circuit, which is limited to 2 amps max (more than sufficient for the XEL's needs). The PSU's normal 5V and12V supplies will of course be used by Dropcheck's XF551 board and floppy drive.

 

For hooking up the XF551 board internally, the XEL has a SIO AUX Port header that can likely supply it's needs...

 

4fdQeDO.jpg

 

2PI4vah.png

 

 

- Michael

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On another note, will it be small enough to fit in a SF314/SF354 case with the 3.5" drive?

 

Not Mini-ITX (too wide for the case).

 

BTW, that picture you took of the XEL motherboard looks great! Fantastic photo quality, with very sharp detail (I'm still trying to get my pics to look like that).

 

- Michael

Edited by mytekcontrols
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Maybe a little clarification is needed. :)

 

I would be supplying a 3 1/2" drive sized (145 x 96 mm) XF551 compatible pcb to fit into an empty 3 1/2" computer case drive bay. Not the drive itself. If you have XYZ drive that otherwise is compatible, it should remain compatible to put into an empty 5 1/4" bay. If you have an additional 3 1/2" computer case drive bay, it is possible you can put an XF551 compatible 3 1/2" drive in it.

 

I will look into directly plugging the board into the SIO AUX connector as a daughter card. The main limitation is going to be size and height constraints. It maybe possible. :)

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I will look into directly plugging the board into the SIO AUX connector as a daughter card. The main limitation is going to be size and height constraints. It maybe possible. :)

 

Or a short ribbon connector to a more convenient parking spot would do the trick if you can'rt make it fit as a plug-in. I wish I had an XEL board to give you as a reference, but it looks like that will have to wait until I have a batch made of the 2nd rev.

 

 

If the drive fits in the case, it should be called the 1088XELD.

I like that :thumbsup: :)

 

- Michael

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Or a short ribbon connector to a more convenient parking spot would do the trick if you can'rt make it fit as a plug-in. I wish I had an XEL board to give you as a reference, but it looks like that will have to wait until I have a batch made of the 2nd rev.

 

 

I like that :thumbsup: :)

 

- Michael

 

Mike, if you can give me dimensions of the free space around the SIO AUX/U1MB connectors going down to the Mini PBI and the min height to clear the audio chips, I might be able to massage the shape/width a little. I've already gotten it down to 96 by 130 mm by going SMD. There is some space to go yet.

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Probably another thread target, but what are the inside dimensions of the ST 3.5 " case?

It is a little larger inside than I remember. About 23cm X 13.5cm X 4.5cm. The original drive is huge compared to a standard 3.5" floppy drive so that would have to be replaced if there is any chance it could coexist with your mini-XF board.

 

This drive case sitting next to a 130XE would be sweet! Regardless though, I will buy one for my 1080XEL if it becomes reality.

 

post-8513-0-54994100-1494475464_thumb.jpg

post-8513-0-89737700-1494475491_thumb.jpg

Edited by Brentarian
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Mike, if you can give me dimensions of the free space around the SIO AUX/U1MB connectors going down to the Mini PBI and the min height to clear the audio chips, I might be able to massage the shape/width a little. I've already gotten it down to 96 by 130 mm by going SMD. There is some space to go yet.

PM sent with scaled PCB layout.

 

- Michael

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It is a little larger inside than I remember. About 23cm X 13.5cm X 4.5cm. The original drive is huge compared to a standard 3.5" floppy drive so that would have to be replaced if there is any chance it could coexist with your mini-XF board.

 

This drive case sitting next to a 130XE would be sweet! Regardless though, I will buy one for my 1080XEL if it becomes reality.

 

attachicon.gif20170510_233503.jpg

attachicon.gif20170510_233428.jpg

 

 

Wow! Foreign end connectors to the 8bit machines.

 

Remember this board is going lean so no real SIO connectors and no power supply.

 

If I tried to build a board to fit the case, I'd have to locate the foreign jacks to have a clean fit and then an adapter cable would have to be made to connect it to an 8bit machine or you would have to cut the case.

 

Not especially a good thing either way. :(

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For hooking up the XF551 board internally, the XEL has a SIO AUX Port header that can likely supply it's needs...

 

 

 

2PI4vah.png

 

 

- Michael

Just out of interest: Is there no need for the other SIO signals on the aux header?

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Update on the option to directly connect the mini-XF551 board directly to the 1088XEL SIO AUX connector:

 

 

Based on the max space I can draw out and measure that I could use w/o interferring with other mods and daughter boards or the ECI or Mini-PBI etc is going to be less than I need. It would also be a crazy shaped board that would scare a teenager half to death. :)

 

I'm afraid my original idea for putting the board in an empty 3 1/2" drive bay is probably the better way to go since I need external facing control access and display as well. Not ideal, but I really don't want to cut up cases either. :(

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Will you quit it :o I can't afford all these extras lol...

 

Seriously though I won't be using a real disk drive in the XEL unless I run a real one off the SIO. But I still think it's a neat idea for those that want to use it.

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Just out of interest: Is there no need for the other SIO signals on the aux header?

For most disk drive related situations the answer would be no. And the main reason I even included this header was to support an internal SIO2SD board. But these same signals could also be routed to an internal SIO floppy disk drive based on the 1050 or XF551 using a suitable cable (i.e., to Dropcheck's XF551 board in a Mini-ITX case's drive bay).

 

- Michael

Edited by mytekcontrols
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This is a very good idea. I support it fully.

A couple thoughts. Could you use Bob1200XL's xf-551 roms so we could use either 5.25 or 3.5 drives. I see these for sale all the time on ebay.

Be sure there is enough clearance for when all the other '3rd party' mods get installed this will still fit properly.

Can you set the default data transfer speed to the fastest available?

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This is a very good idea. I support it fully.

A couple thoughts. Could you use Bob1200XL's xf-551 roms so we could use either 5.25 or 3.5 drives. I see these for sale all the time on ebay.

Be sure there is enough clearance for when all the other '3rd party' mods get installed this will still fit properly.

Can you set the default data transfer speed to the fastest available?

 

I'm debating even offering the OS rom chip. But regardless, you always have the option to replace the existing OS chip. :)

 

I'm not aware of any way to set the default data transfer speed, except maybe in the OS source.

 

Again this board will not directly connect to the 1088XEL mainboard. It will set most likely in an empty 3 1/2 " drive bay, while the floppy drive itself will occupy a 5 1/4 " drive bay.

Edited by Dropcheck
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