RAMX 128K board now available

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RAMX 128K board now available

The RAMX128K board is now available from ReActiveMicro.

 

From the Mythbuster series:

 

TL;DR (skip this if you don't need the details)

 

RAMX - Mythbuster #8 : "We're back!

"Yes, you read that title correctly! With the ROMX line now complete, we've turned our sights onto another line of products. These will be replacements for various motherboard and expansion card RAM chips. First out of the gate will be a new version of the Saturn 128K board. It will have all of the features of the original board including LEDs to indicate the board's status. And it will be 100% compatible. Don't believe others that make this claim because most are not!

 

Which brings us to the first myth to dispel: "all Language Cards and 16K RAM Cards work the same so they are interchangeable." This is not true on many levels. For example, the Language Card has an F8 ROM, many 16K boards handle Reset differently, and compatibility with other ROM and RAM cards is all over the map. Let's see how we got here. Early Apple II's all had Integer BASIC on the motherboard along with what we now call the non-Autostart ROM. When the II Plus came out, these were replaced with Applesoft and the Autostart ROM. In between, we had Applesoft on cassette tape which was loaded into the motherboard RAM. This was soon followed by the Apple II Firmware (ROM) Card which had the Applesoft and Autostart ROMs on a card that plugged into Slot 0. This essentially gave you both an Apple II and II Plus in the same machine with a switch to determine which would be active after a Reset. Software control was also added that allowed DOS to select the appropriate language when a program was loaded. In a glimpse of future-proofing, it is worth noting that this board also had provisions for using the DMA lines of the expansion bus to allow orderly control of similar ROM replacement cards in higher numbered slots. Something like an INHibit daisy chain to a degree.

 

When Apple introduced the Pascal Language System, they realized that by adding another 16K of RAM to the computer, they could replace the motherboard ROM with whatever "firmware" they chose to load into that RAM. This quickly became the de facto standard for most Apple II's - the 64K machine. The original Language Card also contained an Autostart ROM which would always replace the motherboard's F8 chip. This had the advantage of giving old Apple II's the new Autostart functionality without having to swap chips. But since there was no simple way to disable this ROM, it would come back to bite developers of later cards. Unfortunately, it is also notable that Apple did not carry forward the "ROM-sharing" mechanism from the earlier ROM Card. And importantly, this board only had a simple power-on reset circuit to select the motherboard ROM when first turned on. Subsequent Resets would leave the card in its same state (enabled or disabled); this meant that the actual Reset vector could come from either motherboard ROM or the Language Card's RAM. More on this later.

 

The market was soon filled with many clones of the Language Card which eliminated the ROM and were just called "16K RAM" cards. Some even eliminated the usual DIP jumper that was required to operate the Dynamic RAM on the board. What followed next was a slew of boards that offered 64K, 128K, and even more RAM to expand the computer's capabilities. But developers often took different paths in how these boards operated leading to the second myth: "all RAM cards revert to the motherboard ROM on Reset." The Saturn 128 card is a good example because it has been "rebooted" several times. Most of these new designs also lack the ROM-Sharing control as did the Saturn board. But while the original Saturn card followed Apple's lead with the Language Card - a Reset would leave the RAM/ROM selection unchanged - many of the rebooted designs always restore access to ROM on Reset. Since that is the behavior of the IIe and later machines with MMU chips, this is not surprising. But it certainly calls into question anyone who claims 100% compatibility with the original. And that can lead to unexpected results with some software. Worse yet, without the ROM-Sharing protocol it can result in bus contention.

 

Bus contention, or bus fights, happen when more than one device tries to drive the data bus at the same time. When this happens, the data is probably going to be corrupted, large currents can be generated between the competing devices, and hardware failures are even possible. Unfortunately, we still see new boards being designed today that can still cause these ill effects. Which brings us to our first new offering.

 

The RAMX128K board from JD Micro is a fully configurable replica of the Saturn 128K RAM card. It offers 8 banks of 16K with the first bank emulating a ROM-less Language Card or 16K RAM card. Like the original, we have LED's to indicate which bank is active and when the RAM is selected for reading. We added another LED to indicate when the board is enabled for writing as well. And in case you don't like LEDs or the small extra current they require, there is a switch to turn them off. There are also switches to control whether the DMA IN and DMA OUT lines will be used for ROM-Sharing. And finally, you also have a switch to control what happens on Reset: stay in the same configuration or force switching to motherboard ROM. Although DOS and ProDOS handle the warmstart vector to help you remain in Integer/Applesoft correctly, this relies on executing the standard ROM reset routine. If you indeed want to replace that functionality with your own routine loaded onto the RAM card (as many programs do), it would never be executed by a RAM card that always switches back to the motherboard ROM.

 

The original Saturn design was questionable in one other way - Reset does not change the bank selection on the card. So even if you have a custom reset routine loaded into Bank 0 of the card, it might not get called if a different bank is active. While the standard operation of our board is to activate Bank 0 on Reset, you do have the option of complete 100% compatibility with the original Saturn card. The RAMX128K is designed to put you in charge of how the board behaves and also to prevent potentially dangerous bus conflicts. We'll have other RAMX products coming out later this year. Some will have features that have never been available before! So stay tuned...

 

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And it will be 100%

And it will be 100% compatible. Don't believe others that make this claim because most are not!

Dirty approach making ads based on non-specific accusations.  My Saturn 128K clone card is 100% compatible with the original Saturn card, and is in production for over 5 years now:

 

https://www.tindie.com/products/retro_devices/apple-2-ii-plus-e-iie-2e-saturn-rocket-128k-ram/

https://www.ebay.com/itm/315687691862

 

Your inefficient design is using a CPLD with 32 macrocells, while I fit the whole control in a single GAL with 10 marocells which in addition gives me the freedom to use classic trough hole components ;)

You may question the Saturn design but that's the original, like it or not (I think it is quite OK for the era), and the software is made to run only with it, not with nowadays invented by you useless "features" of selected reset behavior, DMA wiring, bla-bla, meant to fool some potential buyers by exploiting their present knowledge. 

 

 

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Fool them how?

... "  meant to fool some potential buyers by exploiting their present knowledge. "

Fool them how?  I think the card is a pretty neat & efficient design.

I have one of your cards ( retro_devices ) and that card is pretty neat too.

Why diss a good design just because it's design concept is different?

 

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retro_devices wrote:...https:
retro_devices wrote:
...

https://www.tindie.com/products/retro_devices/apple-2-ii-plus-e-iie-2e-saturn-rocket-128k-ram/

...

 

You've got it in the wrong category on Tindie. Only you and "Maxwell's Gadgets" are under Home/Supplies/Boards and Shields.

Almost every other Apple II expansion card is under Home/DIY Electronics/Vintage Computing.

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How are these cards different

How are these cards different, better, or worse than the recent Saturn 128K Reboot that was developed and distributed by David Mutimer a few years back?

 

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 baldrick wrote:How are these

 

baldrick wrote:

How are these cards different, better, or worse than the recent Saturn 128K Reboot that was developed and distributed by David Mutimer a few years back?

 

The RAMX128K is quite similar to David's reboot. The major difference is that the RAMX board can be configured to use or ignore the ROM-sharing signals. This allows it to be compatible with any other hardware out there. And the Reset behavior can be set to emulate either the original Saturn card or the IIe and later machines with MMU chips. Both functions have their pros and cons and may be required to work with certain software.

 

For full details, see the first post in this topic or check out the user manual at JD Micro.

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jeffmazur wrote: baldrick
jeffmazur wrote:

 

baldrick wrote:

How are these cards different, better, or worse than the recent Saturn 128K Reboot that was developed and distributed by David Mutimer a few years back?

 

The RAMX128K is quite similar to David's reboot. The major difference is that the RAMX board can be configured to use or ignore the ROM-sharing signals. This allows it to be compatible with any other hardware out there.

The only hardware/firmware I anticipate is maybe your ROMX contemporary device that probably cannot work nicely with vintage RAM cards? I never plan to buy ROMx, and never had it, it is just a speculation from an engineering perspective. Financially it is tricky idea to motivate users to buy an additional RAM card, the only one compatible with that firmware ;)

 

You'd be lucky if your RAM card is not that similar to reboots card, because the latter had been reported to be unstable on muliple configurations/occasions, it may contain design flaws that are mystery to its author too. I am not affiliated with reboots card in any way, just remember giving advice and criticizing its design back in the day when it appeared not only for wasting the resources of 22V10, but David did not listen to me, and I designed my own card with two generic chips only as a proof of my own concept. 

 

 

 

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retro_devices wrote:You may
retro_devices wrote:
You may question the Saturn design but that's the original, like it or not (I think it is quite OK for the era)

 

You are absolutely correct. But staying true to the original Saturn design means that your board may not be compatible with other modern offerings for the Apple II. For exmple, without the ROM sharing option your board will not work with a MultROM card. And with the original Reset behavior - as we discussed in the "Apple II+ hard reset" thread - it will conflict with boards like rallepalaveev's A2RESET.

You may not plan to use these boards, but many others do and would want a solution to this issue. My whole point in writing the Mythbuster article was to point out misunderstandings about RAM cards. The double-reset cold boot and MG ROM++ functions of ROMX+ are quite useful and there's no neeed to criple them by having a RAM card that interferes with them. In fact I would guess that the majority of users prefer the IIe reset behavior.

I'm not sure why your posts seem to indicate a displeasure with other 128K cards. As if you see the RAMX128K as competition to your card. I would not worry. Your board is much more "aggressively priced" and may suit users who do not care about extra features or even gold-plated edge connectors. Just like people can decide between a VW Beetle or a Cadillac, they will choose the product that best serves them.

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jeffmazur wrote:who do not
jeffmazur wrote:
who do not care about extra features or even gold-plated edge connectors. Just like people can decide between a VW Beetle or a Cadillac, they will choose the product that best serves them.
 

 

 

 

Pardon me, it is by no means Cadillac, it is the same VW Beetle but freshly painted with metallic color paint, with new tyres and rims, LED lights, shiny and noisy exhaust gas visible pipes, but the same old VW Beetle, ah , and , of course, with price muliplied by a factor of 4 ;) 

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 baldrick wrote:How are these

 

baldrick wrote:

How are these cards different, better, or worse than the recent Saturn 128K Reboot that was developed and distributed by David Mutimer a few years back?

Here's a video that shows the (little) difference between these cards:

 

https://www.youtube.com/watch?v=TH68hYJvsZ0

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Honestly, @retro_devices, why

Honestly, @retro_devices, why the aggresive, insulting criticism?  Just as a third party observer here Jeff's card looks pretty professional, the price isn't that crazy for how well done the board looks (and it's not 4x the price, not sure why you're exaggerating like that).  It seems like you both are aiming towards completely different markets, so why the insults from the start?  TBH, as a potential customer, your comments turn me off way more than any accusation of JDM's board being somehow... overdone.  It's pretty offputting when most of the good work in this community has come from people collaborating, not fighting each other, and  your comment just reeks of defensiveness.  Nowhere did Jeff mention your card specifically, and there are at least 4 other Saturn clones besides yours floating around eBay, so, rather odd to see this as some sort of direct attack. 

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