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New Hardware: Atari 400 RAM-Card 48/52 KB & external OS-ROM

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Board arrived a few days ago already. Thank you Jürgen!

 

Re. OmniMon: would like to try that as well but am not sure if it's a software only solution as some texts about it claim that it doesn't use any user memory (which to me sounds like it uses some kind of own RAM which would also fit in with the pictures that show a whole piggyback board rather than a replacement ROM chip.

 

If anyone gets Omnimon running with Jürgen's card I'd be interested as well!

 

I suppose faster FP routines would be a possibility as well. More because it can be done than for actual use, I probably won't program a lot on the 400, but some BASIC games would get speedier.

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I would say by the lack of these rom images that

both Omnimon and Omniview were very rare in use

on the 800. This one may only work with the OSN

operating system in place on the ramrod board as

well.

 

Thanks very much for this complete information. I´m always a little bit lost, then in the "main era" of the 400/800 the usage of computers were definitely more common in the U.S. than here in germany - the high prices beginning of the 80s may be the main reason for it. So there are only a few people well experienced with the 400/800 stuff here, and mostly the U.S. expansions were soooooo expensive, nearly nobody has own them. I remember the prices of 800 Deutsche Mark just for a Happy 1050 board. So I know only one - rich guy - having a genuine Happy Inc. 1050 board. All other pay 150-200 Deutsche Mark for garage-made clones :-D

 

ACML... if I ever get something different, I´m please to check it out.

 

Jurgen

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I have installed the board in 52kb mode using NTSC OS ver B from the EPROM. Works great. The DIL adapter is indeed a very tight fit!

I was actually able to plug it in without removing the cartridge guide shell, but it would probably be easier with it removed.

 

I had to adjust the color pot on the CPU board after installation. I may have bumped it when removing the board, not sure.

Here's a photo showing the tight fitting connector. Thanks again Jurgen for making this. :)

 

post-15209-0-94398500-1504310744_thumb.jpg

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I have installed the board in 52kb mode using NTSC OS ver B from the EPROM. Works great. The DIL adapter is indeed a very tight fit!

I was actually able to plug it in without removing the cartridge guide shell, but it would probably be easier with it removed.

 

I had to adjust the color pot on the CPU board after installation. I may have bumped it when removing the board, not sure.

 

Yes, it´s absolutely no free space, but I tried it at three different 400 mainboards, works fine. I didn´t find smaller of these DIL adapters, and without using them, a lot of solder work must be done. I want to prevent the user from soldering too much :)

 

Good point with the color pot - thanks! I´m sure you haven´t bumped it... the color pot is fed by the 12 volt rail in all Atari 400/800 systems. These 12V are connected to the SIO port (and mostly never used) and to the RAM slots. The genuine Atari RAM cards are equipped with 16 KBit DRAMs which require +12, +5 and -5 volts. When using my RAM card, only +5V is used. So the voltage of the 12V rail will increase a little bit, because there´s no load except the few mA used by the color pot circuit - and changing of the input voltage has an immediately effect on the color setting.

 

I will include this behavior in the manual ;)

 

Jurgen

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I would like a board if they are still available. I just found this post and recently got my first 400. What is the total cost and how does one pay?

 

You got mail :)

 

@All: This was the last, not reserved piece. If there´s more demand in the next time, I will made a 2nd batch of course.

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This is what happens when you take a couple of years off Atari-ing.

I would very much like one of these if you make another run. For now my 400 is just a piece of art

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This is what happens when you take a couple of years off Atari-ing.

I would very much like one of these if you make another run. For now my 400 is just a piece of art

 

I have some at stock. PM sent!

 

Jurgen

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Hi. I'm an electronics hobbyist (not a very good one, but a voracious reader). I don't follow this board closely, and missed out on this announcement. I actually stumbled into this while searching for any open-source reproduction PCBs for the original Atari 400 48K board. (Which I might try to replicate someday, and just post to GitHub or OSHPark... but I haven't done much with Eagle or Kicad yet so a ways off..).

Is there a blog post with some details about the choices you made while designing? This is where my current interest lies - the why and how for parts selection..

 

~25 euros is a good deal, but I already have the parts to upgrade the 400 to 48K. Although IF there's a path to get Omnimon or a 400 OS patched for Sio2BT + faster I/O, that's a strong pull to get me to order this on the next round of orders.

 

I noticed this uses "m144 3802", same as with Dropcheck's SpartaDos cart from a few years back. I couldn't Google a spec sheet for this part, not sure what it does. My guess is that it's some kind of GAL or small FPGA, but to what purpose? Translating calls from the Atari, my guess, but to what purpose? (I see the RAM is surface mount, but I can't tell if it's some kind of newer RAM working at different speed than original Atari).

 

Above is more thoughts that questions, but just looking to learn more. :-) One real question I have is, if this has a GAL or FPGA, and therefore quite a bit of flexibility... what else would it have required to make a board that supported Axlon memory? Obviously some increased part cost, but by how much? And what other issues would that cause?

 

Thanks for doing this, and thanks for any time you can spare to respond. Cheers. -Scott

Edited by scottinNH

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Hi,

 

the marking "m144 3802" is just a production label from the pre-owner. I purchased these chips in a lot of one-time programmed, but never used "NOS" chips. It´s a GAL22V10, a simple PLD.

 

The reason for usage is simple: Just one logic chip needed. The original Atari 64 KB board uses 5 or 6 TTL chips and DRAM. Because I decide to use cheaper and stress-free SRAM, I also need less logic terms. That´s why I take the EPROM option additional to this card.

 

Maybe the Axlon memory expansion is also possible, but personally I haven´t any infos about it. I´m not sure if they are ever offered for an Atari 400? Maybe only for an Atari 800, but other´s here should know it better.

 

Then it should be examined if there´s much software using this kind of expansion. I never saw a program requiring or supporting the Axlon memory expansion. But, of course, the 400/800 series were more rare here in Europe than in the USA.

 

My goal was just to have a simple and cheap possibility to USE an Atari 400. I have had some in my basement, only with 16 KB, not usable really for anything else than old game cartridges. As BEST Electronics doubles the price for the Atari factory one, I would pay nearly 50 Euros and more each (incl. shipping and taxes). That´s why I make my own thing :)

 

Jurgen

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Hi,

 

the marking "m144 3802" is just a production label from the pre-owner. I purchased these chips in a lot of one-time programmed, but never used "NOS" chips. It´s a GAL22V10, a simple PLD.

 

The reason for usage is simple: Just one logic chip needed. The original Atari 64 KB board uses 5 or 6 TTL chips and DRAM. Because I decide to use cheaper and stress-free SRAM, I also need less logic terms. That´s why I take the EPROM option additional to this card.

 

Maybe the Axlon memory expansion is also possible, but personally I haven´t any infos about it. I´m not sure if they are ever offered for an Atari 400? Maybe only for an Atari 800, but other´s here should know it better.

 

Then it should be examined if there´s much software using this kind of expansion. I never saw a program requiring or supporting the Axlon memory expansion. But, of course, the 400/800 series were more rare here in Europe than in the USA.

 

My goal was just to have a simple and cheap possibility to USE an Atari 400. I have had some in my basement, only with 16 KB, not usable really for anything else than old game cartridges. As BEST Electronics doubles the price for the Atari factory one, I would pay nearly 50 Euros and more each (incl. shipping and taxes). That´s why I make my own thing :)

 

Jurgen

 

Well,

 

Axlon was founded and lead by Nolan Bushnell, it was a 100% daughter of Atari. Many moons ago, I contributed to the A8FAQ maintained by M.Current. There were some topics about ramdisks/XRAM, programs that supported ramdisks/XRAM and programs that required ramdisk/XRAM. While the majority of them were for XL/XE computers, I also noted Axlon and Mosaic and once collected a list of programs that supported them. Nowadays these topics and especially the looonnngg lists have been removed from the A8FAQ, but originally the lists also included some programs that support Axlon or Mosaic. All that is left today is in the "to do" notes:

 

- programs supporting Axlon or Mosaic banked memory

    Axlon list: OmniWriter,     Mosaic list: RAMbrandt

But you can find a very old version of the A8FAQ at atarimania (this one does not have the list of programs supporting Axlon or Mosaic however): http://www.atarimania.com/faq-atari-400-800-xl-xe-what-kinds-of-extra-ram-and-ramdisks-can-be-installed_73.html

http://www.atarimania.com/faq-atari-400-800-xl-xe-what-programs-support-more-than-64k-ram_74.html

http://www.atarimania.com/faq-atari-400-800-xl-xe-what-programs-require-more-than-64k-ram_75.html

 

Many applications from the 1980s like Visicalc, Syncalc, Synfile, etc. did either support Axlon or Mosaic. Afaik, Atari 400/800 normally had a max. of 48k main/base RAM and it was the Axlon or Mosaic enhancement that gave them up to 52k main/base RAM (think with the 64k Mosaic upgrade board that bankswitched in the $C000-CFFF region), like your upgrade does. Found also a few 80s programs that gave you more RAM with a 400/800 or its OS than with a 64k XL/XE or XL-OS, e.g. Howfen-DOS and Howfen Tape to Disk when used on a 64k XL/XE machine (with XL-OS) do have 4k less RAM than the same programs used on a 400/800 or an XL/XE with OLD-OS. Since I do not own a 400/800 computer nor a Mosaic or Axlon RAM enhancement its up to other Atarians to create a list of programs that support these old upgrades. Afaik, the new Sophia board also offers Axlon modes, but again, I do not own it...

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