Atari 1090XL Schematics?

[+tf_hh]

From the datasheet, it looks like all it needs is some sort of external clock to drive it rather than a crystal.

But if this is for a new project, I think it makes more sense to use a more modern UART, preferably one that has built-in FIFO buffers, since they would support higher baud rates with lower chances of overrun due to the 6502.

 

I would suggest using the 16C550. Also an old, but good UART. Some manufacturers produce them until now, so they are availible.

 

Like this IC, it´s easy to handle and need almost nothing special external components. Just use a oscillator for the baudrate generator, level shifter (1488/1489 or, if only 5V present, one or two MAX232), ready. Also good for "low speed" systems... the 16C550 supplies Auto-Hardware-Handshake, means than CTS/RTS must not set by the computer (if enabled), the UART will handle itself. And you can support also DTR, DCD, RI and so on... I like full serial ports, not only RxD/TxD.

 

When I´m remembering right... somebody in the early 90´th years has publish such a solution with a Atari 850 compatible driver. Maybe anyone knows about this project?

 

Jurgen

[Dropcheck]

Hello Dropcheck and others of course.

 

I have several 6551 chips. (10+) and I'm willing to part with them.

Disadvantage is the high shipment cost if the go from NL to USA. (About $27 or so)

 

Also, I fail to see the use of an RS232 port as we have many good alternatives right now.

But if someone wants to make it, of course it's nice.

I have made the hardware long ago. See attached file.

This may very well be (almost) identical to the design from Germany.

 

I do have very good schematics for the 600XL and 800XL.

They are copies of Original Atari schematics, size A2.

So I'll try to scan them and then post those here.

 

BR/

Guus Assmann

 

 

Hello Guus,

 

I realize there's probably better alternatives. And maybe not much need for serial and parallel ports at all. But I was trying to keep as much original intention as well as implementation. Who knows with a completed box, someone might actually try to hang a modem or printer off the ports. If only for the pictures.

 

I thought I saw your fingerprints all over the schematics. Thanks for the offer of the 6551. Let's put hold on it for awhile, until we are more sure what direction we're going. I'm still in the research phase at this point. Seeing what's out there and what makes sense to include. Or leave open for others to make.

[Dropcheck]

Here's a contender for the parallel port. Again from Igor's website. It's part 1 of a 3 part discussion on the Atari Centronics interface.

[Dropcheck]

I've done a mockup on what the pcb could look like. It's still rough and doesn't have all the circuitry included yet, but it will give you an idea of what it could be.

 

PCB is 200 X 200 mm

 

[+mytek]

Looks very nice

 

Ever give any thought to using switching regulators in the power supply design? I have a schematic somewhere for something I built a few years back that only required a couple of inductors, capacitors, a diode, and a switching regulator IC that worked quite well for up to 3 amps with very little heat dissipation. If you're interested I'll see if I can find it and post it here. I also have a populated 600XL motherboard that would be great for tracing out circuit connections on, do you still need this to be done or I can loan it to you?

 

- Michael

[guus.assmann]

A switching regulator? Buy it in China. Can't build it yourself at those prices.

 

As promised, the schematics in attachment.

And I'm quite sure they are acurate.

It's what I used when I was repairing the computers for Atari.....

Enjoy. And saves time, no need to trace out a board.

 

BR/

Guus Assmann

600XL_Part_1.pdf

600XL_Part_2.pdf

800XL_Part_1.pdf

800XL_Part_2.pdf

[+mytek]

A switching regulator? Buy it in China. Can't build it yourself at those prices.

 

BR/

Guus Assmann

 

I respectfully disagree. The switcher I designed does not use fancy transformers nor does it deal with High Voltages, all of which incrementally increase the price. This switcher is essentially a one-chip solution that runs off of a low voltage DC input. For a regulated 5 VDC output, as little as 9-10 VDC coming in will do it. And IIRC the input can be as high as 36 VDC. I do believe there is also a similar 12 VDC output device in this same family. Besides the chip, it only requires a couple of inexpensive components. This is an actual switcher on a chip, and should not be confused with linear regulators like the 7805 or 7812. As I said I'll dig up my plans and post it here by tomorrow.

 

- Michael

 

EDIT: I found the 1 amp switcher I made based on the LM2595 (I'm still looking for my 3 amp power supply design).

 

 

 

Here's how simple it can be made in its minimal form (can't get much simpler than that).

 

 

 

And here's my design including a a little more filtering since I was using this on an analog board.

 

Edited May 26, 2016 by mytekcontrols

[Dropcheck]

 

I respectfully disagree. The switcher I designed does not use fancy transformers nor does it deal with High Voltages, all of which incrementally increase the price. This switcher is essentially a one-chip solution that runs off of a low voltage DC input. For a regulated 5 VDC output, as little as 9-10 VDC coming in will do it. And IIRC the input can be as high as 36 VDC. I do believe there is also a similar 12 VDC output device in this same family. Besides the chip, it only requires a couple of inexpensive components. This is an actual switcher on a chip, and should not be confused with linear regulators like the 7805 or 7812. As I said I'll dig up my plans and post it here by tomorrow.

 

- Michael

 

 

The power supply would have to provide enough current for at least 1 rather old hd plus the multitude of chips via the expansion slots plus all the onboard circuitry. I would say 12V at 1A at least. 5V at 1A. I added the 3..3V for more modern chips. Not sure what the A would be, but lets say .5A at least.

 

What I currently am using is the LM2596S in 12V, 5V and 3.3 V configurations. It provides the step-down switching regulation capable of driving upto 3A with appropriate DC input from a AC to DC adapter. Two caps, 1 inductor and a diode per LM2596S.

[+mytek]

 

 

The power supply would have to provide enough current for at least 1 rather old hd plus the multitude of chips via the expansion slots plus all the onboard circuitry. I would say 12V at 1A at least. 5V at 1A. I added the 3..3V for more modern chips. Not sure what the A would be, but lets say .5A at least.

 

What I currently am using is the LM2596S in 12V, 5V and 3.3 V configurations. It provides the step-down switching regulation capable of driving upto 3A with appropriate DC input from a AC to DC adapter. Two caps, 1 inductor and a diode per LM2596S.

 

Yep I do believe that is the chip I used in my 3 amp switcher as well. So it looks like we are on the same page

 

I just couldn't tell from the layout you posted what was the case.

 

- Michael

[Bryan]

You can also just drop something like this into the case:

 

eBay Auction -- Item Number: 111702971268

[Dropcheck]

You can also just drop something like this into the case:

 

eBay Auction -- Item Number: 111702971268

 

An idea..... a little overkill though. Maybe this would be better.

 

But it's not really a dropin. You'd still have to wire the on/off switch and AC input plug. Then create the 3.3V circuit. It would make the case bigger and heavier as well. Trade offs.

[guus.assmann]

_{Well, I was thinking of the same kind of design.}

_{But if you go to Ebay and enter: "LM2596S-ADJ Adjustable DC-DC Buck Regulator" then you can buy a complete PCB with all compomentent for about $1,50.}

_{This includes the LM, capacitors, coils, pot and PCB.}

_{For me, it's impossible to buy all these components at such a price.}

_{And I've used these kind of units to replace the LM7805 and LM7812 in my 1050 drive.}

 

_{> OFF TOPIC <I}

_{n some way, I don't like this.}

_{I cannot understand how this is possible at those prices.}

_{Do we pay too much? Or do we pay a realistic price that enables research. Companies do need profit of course.}

 

_BR/

_{Guus Assmann}

[Dropcheck]

Hi Guus,

 

Or how about this?

 

It's got to be volume based to make any kind of profit. And still you have to understand that in China the companies are much, much more heavily subsidized than in Europe or the US.

 

Edit:

 

I've picked up both the LED version and a double order of the plain jane LM2596 adjustable modules. About $15.00 with shipping. Far less than what I could do myself. Only bad thing about it is the wait time. I want it now........ As it is it'll be two to three weeks. Oh well.,.. I'll just have to find something else to do.

Edited May 27, 2016 by Dropcheck

[+tf_hh]

Hi,

 

just my 2 cents to the power discussion.

 

1. Use your own parts. The difference in pricing is too small to earn the headache if something went wrong. I´ve bought some of these 1-2 USD regulator PCBs in china some time ago. 50% uses faked chips (500 mA version real, declared at 1 Amp and so on). The solder quality is bulls*it sometimes. The space around and so on is fixed to THAT one PCB you´ve ordered from china. Next order you get something totally different, even if the photo is the same before...

 

2. Don´t use open frame PSUs. I don´t know the legal situation and law in the U.S., but in europe YOU have to pay for all that can happen with such an open frame PSU. Fire, electric shock, death. As a private tinkerer or smallest business (wo-) men it´s better to use "ready-to-use" external PSUs. You can get 12V 5A stabilized external PSU for around 10-12 USD/Euros. Use such a thing... 12V input, step-down to 5V and 3,3V for your needs with own parts.

 

Jurgen

 

[ricortes]

_{Well, I was thinking of the same kind of design.}

_{But if you go to Ebay and enter: "LM2596S-ADJ Adjustable DC-DC Buck Regulator" then you can buy a complete PCB with all compomentent for about $1,50.}

_{This includes the LM, capacitors, coils, pot and PCB.}

_{For me, it's impossible to buy all these components at such a price.}

_{And I've used these kind of units to replace the LM7805 and LM7812 in my 1050 drive.}

 

_{> OFF TOPIC <I}

_{n some way, I don't like this.}

_{I cannot understand how this is possible at those prices.}

_{Do we pay too much? Or do we pay a realistic price that enables research. Companies do need profit of course.}

 

_BR/

_{Guus Assmann}

I fool around with audio a bit. Lot's of chips coming out of China are fakes, manufacturer dropouts, counterfit, and just plain mislabeled. Rumor has it that a lot of chips are just lessor chips with markings cleaned off and restamped with a more expensive ID. Something like a chip that is designed to operate at 13 V for automobile applications is labeled as one for 37 V for home audio. Most big suppliers like Digikey are pretty good at getting real chips but I wouldn't trust anything from eBay.

 

Design theft is pretty rampant in Asia too. Remember all those monitors and equipment that went out due to bad capacitors? IIRC: One company had good success with a new electrolyte formula. The WRONG formula was stolen and sold to several other capacitor manufacturers and went out through the supply chain. Wild West for electronics right now.

[Dropcheck]

I've made a couple of edits to the 1090XL original schematic. Please throw away the old and download the new schematic. You can find the link a page or so back in the thread.

[Bryan]

I fool around with audio a bit. Lot's of chips coming out of China are fakes, manufacturer dropouts, counterfit, and just plain mislabeled. Rumor has it that a lot of chips are just lessor chips with markings cleaned off and restamped with a more expensive ID. Something like a chip that is designed to operate at 13 V for automobile applications is labeled as one for 37 V for home audio. Most big suppliers like Digikey are pretty good at getting real chips but I wouldn't trust anything from eBay.

 

Design theft is pretty rampant in Asia too. Remember all those monitors and equipment that went out due to bad capacitors? IIRC: One company had good success with a new electrolyte formula. The WRONG formula was stolen and sold to several other capacitor manufacturers and went out through the supply chain. Wild West for electronics right now.

Sure but the more common and cheap a part is, the less likely it is to be counterfeited. Where you really have to watch out is when buying rare, discontinued stuff like transistors for vintage amps.

[bugs]

Very exciting project dropcheck. I declare interest in 1.

 

Sent from my SM-G920W8 using Tapatalk

[sup8pdct]

I don't sucome to hints. Nup.never.....

 

Well I've managed to put together a prelim schematic for the 1090XL Prototype board as far as the expansion part is concerned. It does not include the power supply part. I leave that to someone else (hint....hint....)

 

 

 

P.s I did a little work on this rainy day.

 

 

1090xl power schematic Model (1).pdf

 

 

James

 

[danwinslow]

Well, on risk of being condemned, and as much as I want to see this being as 'old school' as possible, I have to admit I think it would be cool to have a USB adapter in there. Something like the USB cart that came out several years ago.

 

[+David_P]

Or how about an ethernet card?

[evilmoo]

Another thing I was wondering: Where is the firmware for all of this stuff going to fit? I think the Black Box and MIO both chewed up multiple PBI device IDs because they didn't have enough firmware space. Is it feasible to bank select the upper half of each device's PBI ROM?

[evilmoo]

Or how about an ethernet card?

 

In theory, that could be run off of a USB port.

[flashjazzcat]

Another thing I was wondering: Where is the firmware for all of this stuff going to fit? I think the Black Box and MIO both chewed up multiple PBI device IDs because they didn't have enough firmware space. Is it feasible to bank select the upper half of each device's PBI ROM?

Devices may bank switch their PBI ROMs any way they see fit.

[sanny]

Or how about an ethernet card?

 

But isn't this (or an USB card) "later"?

 

First the expansion box and then the extension cards...