Seeking for an apple2 experts advice here. Is there any software except for the original Saturn RAM card's tests that rely on or check for the *double* consecutive read accesses to C0x1 or C0x3 or C0x9 or C0xB in order to write enable the (language) RAM card? I am asking this because I've designed a 128K RAM card that accepts only a single such access and all software I tested worked except for the Saturn specific RAM card test that complains with a message "RAM WRITABLE WITH ONE POKE" which strictly speaking is incorrect since they mean a PEEK.
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Language 16K RAM card or Saturn 128K RAM card access advice welcome
- Thread starter george
- Start date
David_M
Veteran Member
A read or write will activate the soft latches so peek or poke will work.
There is a page in the Saturn card documentation that details how the soft switches work, I used it to design the Satrun128 Reboot card.
There is a page in the Saturn card documentation that details how the soft switches work, I used it to design the Satrun128 Reboot card.
Anthony Adverse
Experienced Member
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- Oct 18, 2018
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Is there any reason there couldn't be a saturn 256? Or is it just pointless, or exceed the number of banks swappable?
A
A
This page does not describe all peculiarities of the saturn card's control. My main question was about the *double* access. What if single access was sufficient? This would have saved one output pin in the 22V10 if used to emulate the saturn card. On the other hand the saturn card differs from the language cards because a write access to C0n1 also works in Saturn for enabling the write access to the card's RAM. Moreover the Saturn testing software specifically checks if this is possible and refuses to detect the card at all if only read (like in language cards) is required at an odd C0nx. Another difference -- at power-up unlike the language cards the Saturn card is disabled for writing.
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David_M
Veteran Member
I created a Saturn card last year and some lowlife in Russia has already ripped off the design and is selling poor quality pcbs.
Why redo it again? It would be far more useful to find another card to redesign.
This is my current pcb alongside the rom card i designed.
Anthony Adverse
Experienced Member
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@george All to true, but I had wondered why they stopped at 128.... interconnectivity doesn't mean interoperability 
Because back in 1982 this was enough and expensive enough@george All to true, but I had wondered why they stopped at 128.... interconnectivity doesn't mean interoperability
@ David your design has stability issues (according to the corresponding topic in the applefritter forum and not only) and wastes the 22V10 while adding 3 more '74 ICs to it. The PCBs of the Russians are not that bad (if they are correct?) but are expensive for the purpose. Don't plan to try them. I have my own ideas. I thought that your project was an open project since is a bit crude so far...I thought maybe you had released it exactly because it has problems in order for others to improve and fix them.
@ groink David himself has published two versions of his GAL firmware in the applefritter forum. I personally have never investigated them since I have an original saturn card (as a model for my project now).
David_M
Veteran Member
Because back in 1982 this was enough and expensive enough
@ David your design has stability issues (according to the corresponding topic in the applefritter forum and not only) and wastes the 22V10 while adding 3 more '74 ICs to it. The PCBs of the Russians are not that bad (if they are correct?) but are expensive for the purpose. Don't plan to try them. I have my own ideas. I thought that your project was an open project since is a bit crude so far...I thought maybe you had released it exactly because it has problems in order for others to improve and fix them.
@ groink David himself has published two versions of his GAL firmware in the applefritter forum. I personally have never investigated them since I have an original saturn card (as a model for my project now).
There are no stability issues other than faulty RAM chips. As "crude" as it is I was able to make it work with just the page from the saturn manual... you apparently can't. So forgive me if I don't place any value on your opinion.
The topic in applefritter only (I heard about FB too) is full of reports that your ram card not stable on different machines. And I may know why. But as you say this has no value to you and your ram card will remain buggy. I refrained from saying this but no more -- just one look at your amateurish PCB design with the track thickness of the power supply and many other issues I am no longer wanting to tell you since you treat all remarks with silence, hostility and contempt and haughty. BTW these your words tell me that you are not fully aware of what is going on with your design:
David_M
Veteran Member
You make a lot of assumptions, unfortunately most of them are wrong.
My assumptions are right and unlike you I would have listen to your logical arguments that you never provided. When I wrote you in another forum that only a 22v10 should be enough to control the SRAM chip I meant it. You opposed stubbornly to my observations and I decided to design the RAM card myself...
http://www.ebay.com/itm/264218272308
David_M
Veteran Member
How is your butthurt coming along. I hope it is healing now.
I guess this attitude leads to your design flaws, but it could be something general -- for instance Australian law that kills cats...