1090XL remake

[reifsnyderb]

Ok.  So the chassis should be about the flat section of a 1450XL?  I don't know what those dimensions are other than estimating at maybe the depth of a 1050, width of a 600xl, and height of a 1050 + 800xl.  (Personally, I'd go for a footprint the size of a 1050 and just a little bit higher and see if it would fit.)

 

Well, the main board doesn't have to be that big.  Printing a chassis that big could be a problem, though.

 

 

 

 

[+kheller2]

The 1090 was about the size of two 1050s stacked, at least height wise.  

[reifsnyderb]

Ok.  I'll see if I can shrink the board down by using modern components and a more compact design.  I'll also add the HALT line and RD5 line as I mentioned earlier.  The +12 and -12 will be kept as well.  The space for the chips can be reduced even with through-hole components, though I'd rather go with SMD for the chips.  A goal will be to keep the 2 layer design, though, so as to keep the cost down.  I think the spacing between the card slots should be kept but the space taken up by the power supply section can be reduced by using smaller components.  Modern capacitors, for example, are usually a lot smaller.  Putting in a separate +5vdc voltage regulator for the cards may be a good idea as well so as to reduce the need for separate voltage regulators on each board.

Edited January 7, 2022 by reifsnyderb

[kenames99]

the HALT is really not needed since the address bus is output only from the computer. RD4 can be generated inside the 1090XL using sw and hw techniques. a 1090XLmini should have identical driver/buffer as the full size one. if there are changes to circuitry, it should be named something else. my 2 cents worth.

 

Ken

 

[Mathy]

Hello guys

 

I was under the impression that the Mega-ST cases were made (size wise) with CRT monitors in mind.

 

My CM8833 is roughly 35 x 35 cm BTW.

 

Sincerely

 

Mathy

 

[_The Doctor__]

Halt might have some interesting uses, set up the some things and then halt the 6502 cpu with an external speeder stuff the buss in some way... might need some modification , halt is useful for Antic banking, it might be useful for who knows what on a 1090 card... I understand his desire to include it just in case there is some arbitration for whatever purpose being needed. Give external thing something to do halt the cpu until it's done and then come back up avoiding a bunch of extra code etc. Something crafty could come of it... just rambling there... are there any more important signals that folks absolutely can't find a way around?

Edited January 8, 2022 by _The Doctor__

[reifsnyderb]

I am thinking that developers would need to be made aware that in order to use /HALT and RD5 that they would have it made very clear that these are using pins that normally are NC inside the Atari and the only way to use them is to add the right jumpers to the Atari.  So, if you want to develop something that is more usable to the majority you don't use the extra pins.  If, on the other hand, you want to develop something that has a cool feature but much smaller audience then you have that option.

 

Personally, I don't object to using the reserved pins for some important function but I wouldn't develop cards that use them because I'd like more people to be able to use the cards I develop.

 

What's the consensus on my adding a voltage regulator for +5vdc and running power to the cards as that isn't on the original specification?

 

Edited January 8, 2022 by reifsnyderb

[reifsnyderb]

46 minutes ago, _The Doctor__ said:

Halt might have some interesting uses, set up the some things and then halt the 6502 cpu with an external speeder stuff the buss in some way... might need some modification , halt is useful for Antic it might be useful for who knows what on a 1090 card... I understand his desire to include it just in case there is some arbitration for whatever purpose being needed. Give external thing something to do halt the cpu until it's done and then come back up avoiding a bunch of extra code etc. Something crafty could come of it... just rambling there... are there any more important signals that folks absolutely can't find a way around?

I just re-read your thoughts.  I was thinking to just have it detect the halt signal so that Antic banking is possible.  I am not sure that Antic would be happy with something else generating a halt signal.  Maybe someone could answer this as having the ability to halt the bus from the 1090 could be interesting.

[_The Doctor__]

I left banking out of my text? I fixed it 'halt is useful for ANTIC banking, it might be useful....

would you be able to discretely supply 5V with sufficient current for all of the cards? The old design with each card having it's own 5V regulation sort of covered things in that sense... but I don't see any harm in a 5 volt supply being included... with no back feeding to the Atari though...

[reifsnyderb]

2 minutes ago, _The Doctor__ said:

I left banking out of my text? I fixed it 'halt is useful for ANTIC banking, it might be useful....

would you be able to discretely supply 5V with sufficient current for all of the cards? The old design with each card having it's own 5V regulation sort of covered things in that sense... but I don't see any harm in a 5 volt supply being included... with no back feeding to the Atari though...

There wouldn't be any back feeding to the Atari unless somebody made a card that did that for some reason.  The signal and data lines, of course, would have voltage to them through the chips that handle these signals.

 

While it depends upon how much current a card uses, one LM7805 can handle up to 1.5 amps.  So it should be fine for logic chips.

[reifsnyderb]

Looking for card edge connectors.  They are horribly expensive.  I wouldn't be surprised if the card edge connectors cost $50 per board.   ?

 

 

Edit:  They can gotten cheaply at Aliexpress.....unfortunately.  ($7.22 for 5 where Mouser wants almost $10 each.)

Edited January 8, 2022 by reifsnyderb

[reifsnyderb]

Ok.  After spending a little time looking at this I don't see where we'd get anywhere going to surface mount components.  This is mainly because the power supply capacitors take up so much space.  So, if we go with surface mount components we still end up with a big board.  ?  Also, it's interesting that there are two choices of chips to use...which could come in handy with our current chip shortage.

 

So, after all that, I think it's best if we just go with the through-hole components.  Since no space was found, cards will have to have their own voltage regulators as it makes no sense to add 5 vdc to the bus now.

 

However, it may still be possible to add the HALT and another line (RD5?) for those who want to tinker with it.  I'll look into that possibility.  But, once again, these lines would only be available to someone who wants to solder jumpers in their Atari.  (I just looked at the XE spec and the 14-pin extension connector has HALT as pin C.  So, adding HALT was thought of with the XE but not the XL.)

 

The chassis can come later and be 3d printed.

 

I suppose some boards with parts and accessories could be gathered together as developer kits or something like that.....    Build or print your own chassis???

[+x=usr(1536)]

2 hours ago, reifsnyderb said:

What's the consensus on my adding a voltage regulator for +5vdc and running power to the cards as that isn't on the original specification?

Please don't.

 

I'm somewhat concerned that the original idea of recreating the 1090 as best as possible from what is known of its spec is drifting into 'build a generic peripheral to do 1090-alike things' territory.  If this is how things ultimately end up, my interest in the project will be gone.  This doesn't mean that modern components and design techniques can't or shouldn't be used where possible in order to improve performance or save space, but this is a case where - to my eyes, at least - better is the enemy of good enough.

 

Note that I say that as a three-time FujiNet purchaser.  Modern hardware absolutely has its place alongside our original hardware, and by no means am I in any way, shape, or form opposed to it.  But in this specific instance, those same modern improvements would effectively eliminate what interested me in the device in the first place.

[reifsnyderb]

I just realized that Pins 39 and 47 on the PIA are already connected to every card in the 1090 bus.  Pin 39 is a reserved pin and could be used for RD5 without any changes.  Pin 47 is +5VDC on the 600XL only.  So, on a 600XL, all the cards are getting +5VDC from the computer.  Very interesting.

 

So, really, the only optional change to the 1090 would be to add the /HALT line.  That's it.  Nothing else.  Since the /HALT line is added to the expansion connector on the 130 XE it's not something Atari engineers didn't think of at some point.  If somebody has a 130XE they could use that line with an adapter or special connector....which they would need anyhow.

 

 

 

[reifsnyderb]

Here's the KiCad with the /HALT line added.

 

/HALT is on pin 33.

Pin 39 was already connected, but reserved, and could be used for RD5.

 

On the XL, both lines would have to be connected internally, of course.

 

Edit to add:  This was taken from Ken's Github files and modified.  So credit goes to him for this and I just added one connection.

 

Edit to add:  Gerbers in the .zip file need re-generated as they are for an unmodified 1090XL.

 

1090XL w HALT.zip

Edited January 8, 2022 by reifsnyderb

[+Spancho]

10 hours ago, reifsnyderb said:

 

What's the consensus on my adding a voltage regulator for +5vdc and running power to the cards as that isn't on the original specification?

 

I think that makes absolutely sense. Since there are 5 card connectors the supply of maybe 5x 500mA needs to be accounted for.

[Dropcheck]

9 hours ago, reifsnyderb said:

Looking for card edge connectors.  They are horribly expensive.  I wouldn't be surprised if the card edge connectors cost $50 per board.   ?

 

 

Edit:  They can gotten cheaply at Aliexpress.....unfortunately.  ($7.22 for 5 where Mouser wants almost $10 each.)

Here's a source I've used frequently.  He's reliable and reasonably quick to ship.  Shipping is a little steep though.  Ebay

 

I think he also has the same format in smaller numbers, say 5 or 10.

Edited January 8, 2022 by Dropcheck

[Nolium]

10 hours ago, reifsnyderb said:

Looking for card edge connectors.  They are horribly expensive.  I wouldn't be surprised if the card edge connectors cost $50 per board.   ?

 

 

Edit:  They can gotten cheaply at Aliexpress.....unfortunately.  ($7.22 for 5 where Mouser wants almost $10 each.)

Perhaps this will help

https://www.aliexpress.com/item/4000490392119.html?spm=a2g0o.cart.0.0.1bca3c00X38ndu&mp=1

[+kheller2]

10 hours ago, reifsnyderb said:

I just realized that Pins 39 and 47 on the PIA are already connected to every card in the 1090 bus.  Pin 39 is a reserved pin and could be used for RD5 without any changes.  Pin 47 is +5VDC on the 600XL only.  So, on a 600XL, all the cards are getting +5VDC from the computer.  Very interesting.

 

So, really, the only optional change to the 1090 would be to add the /HALT line.  That's it.  Nothing else.  Since the /HALT line is added to the expansion connector on the 130 XE it's not something Atari engineers didn't think of at some point.  If somebody has a 130XE they could use that line with an adapter or special connector....which they would need anyhow.

 

 

 

Are you sure about the +5 from the 600XL?  I thought I read that line would not be passed through and is only for the 1064 which I think also doesn’t pass it.  I haven’t looked.  So I’m probably wrong. 

[reifsnyderb]

4 minutes ago, kheller2 said:

Are you sure about the +5 from the 600XL?  I thought I read that line would not be passed through and is only for the 1064 which I think also doesn’t pass it.  I haven’t looked.  So I’m probably wrong. 

Yes.  Pin 47 is connected through the 1090 but pin 48 is not.  My guess is it could be considered a 600XL sense line.  (If there is +5 VDC, a 600xl is detected.)  

 

As per the schematic, the 1066 doesn't use it.

The 1064 uses pins 47 and 48 for +5vdc from the 600XL.

 

[reifsnyderb]

3 hours ago, Spancho said:

I think that makes absolutely sense. Since there are 5 card connectors the supply of maybe 5x 500mA needs to be accounted for.

I decided against it.  The capacitors take up too much space on the board and it didn't make sense to go to SMD because there wouldn't be any size reduction in the board.  So all I added was an extra line that can be used for /HALT if someone wants to tinker.  (It's hard to tell it was even added.   ?   )

[+kheller2]

3 hours ago, reifsnyderb said:

Yes.  Pin 47 is connected through the 1090 but pin 48 is not.  My guess is it could be considered a 600XL sense line.  (If there is +5 VDC, a 600xl is detected.)  

 

As per the schematic, the 1066 doesn't use it.

The 1064 uses pins 47 and 48 for +5vdc from the 600XL.

 

As per the Parallel Bus Expansion Memory Specifications (1064):

"... it will also provide the interface to the Expansion Box in the rear of the Unit.  The interface will contain all the signals of the P.B.I. except reserved and power (+5VDC)."

 

Then again, one of the 1090 specs shows +5 coming out of the Expansion box, and the other doesn't.

 

Then again again, the 1064 schematics show one edge with +5 on 47/48 "card edge to PBI" and the other without "connector to 600xl", which seems backwards.

 

Since we have real 1064 and 1090s it should be easy to see what was done in reality .. right or wrong.

 

[reifsnyderb]

10 minutes ago, kheller2 said:

As per the Parallel Bus Expansion Memory Specifications (1064):

"... it will also provide the interface to the Expansion Box in the rear of the Unit.  The interface will contain all the signals of the P.B.I. except reserved and power (+5VDC)."

 

Then again, one of the 1090 specs shows +5 coming out of the Expansion box, and the other doesn't.

 

Then again again, the 1064 schematics show one edge with +5 on 47/48 "card edge to PBI" and the other without "connector to 600xl", which seems backwards.

 

Since we have real 1064 and 1090s it should be easy to see what was done in reality .. right or wrong.

 

I was able to get to the atarimuseum.com 1090 schematics using http://web.archive.org 

 

https://web.archive.org/web/20210403131120/http://www.atarimuseum.com/computers/8BITS/XL/xlperipherals/1090xl.html

The 1066 didn't use the +5 from the Atari through pin 47 as per the schematics.

The 1064 does use pins 47 and 48 as per the schematics.

 

The KiCad files I used were from Ken's github and they match the schematics at atarimuseum.com (via web.archive.org)

 

While I'd love to have a confirmation from someone with the actual hardware, I think there is enough information to go with this.  We'll just need some development information available for anyone who wants to make cards for the 1090xl.

 

Well, first we need 1090xl development boards....

 

 

 

 

[ivop]

42 minutes ago, reifsnyderb said:

Well, first we need 1090xl development boards....

Perhaps it's cheaper to just draw one in KiCad and have them made by a Chinese PCB manufacturer. An edge connector with a 100mil grid of through-hole solder pads.

Edited January 8, 2022 by ivop

[reifsnyderb]

2 minutes ago, ivop said:

Perhaps it's cheaper to just draw one in KiCad and have them made by a Chinese PCB manufacturer. An edge connector with a 100mil grid of through-hole solder pads.

Sorry.  I was thinking the 1090xl main board.  I was thinking that we need 1090xl main boards with PBI cables, power supply components, edge connectors, etc.  Then we can use those to make other cards.  I am seriously thinking about ordering the boards and parts myself so as to test my memory card.    ?