Video-7 RGB *without* 64k?

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Video-7 RGB *without* 64k?

Does documentation exist for this card?  I believe it is RGB (it has a 15 connector)  but just not the RAM.  Anyone aware of this card?

 

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Looks identical to the TAXAN 410-80 RGB Card

Looks identical to the TAXAN 410-80 RGB Card for Apple //ehttps://www.applefritter.com/node/24157

 

Here is its manual: https://www.applefritter.com/files/2023/06/11/Taxan410-80a.pdf

 

 

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Ah, great!  Thanks for that. 

Ah, great!  Thanks for that.  If it doesn't have the 64k expansion,  are there other options to provide that?

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TimCross wrote:Ah, great! 
TimCross wrote:

Ah, great!  Thanks for that.  If it doesn't have the 64k expansion,  are there other options to provide that?

I've seen pictures of a sort of "side car" slot splitter for the AUX slot before, but I have mever actually seen one in person and don't know if they are still available.

 

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Oh ok, I haven't seen one of

Oh ok, I haven't seen one of those before.  Maybe that or reverse engineering this board and then adding on the RAM?  Might make for a good project.

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For that card I don’t know of

For that card I don’t know of any available options that’ll give you 64k. There are currently a few options out there for getting HDMI, VGA or component video off a regular slot. There’s also addon cards for the Ramworks that output VGA or component video from A2Heaven as well as a Ramworks clone.

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TimCross wrote:Oh ok, I haven
TimCross wrote:

Oh ok, I haven't seen one of those before.  Maybe that or reverse engineering this board and then adding on the RAM?  Might make for a good project.

 

I remember now that the AUX "side car" slot adapter won't work with your kind of RGB card.  It is for use with the AE style one that goes on the back of a RAMWorks II or III.  It then provides an AUX slot that will work with compact type AUX RAM cards like the Garrett's Workshop ones that use modern memory and have a smaller board size.

 

Unfortunately I think that one of these RGB cards with only 2K of RAM on them (needed for the other 40 columns of text) is of extremely limited usefulness since it can't even support double hires modes.  It is kind of a historical anachronism in a way.  It is weird someone would spend all the money for an expensive RGB color monitor (they were PRICEY back then) and then cheap out on the video card and not get the extra 64k...  Obviously it happened but you really have to wonder what they were thinking, and can imagine a lot of regret soon thereafter when they found out they really needed that additional 64k to run most of the interesting //e specific software like Appleworks even.  A lot that didn't absolutely require 128k sure worked a lot better with it.

 

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Now that I’ve thought about

Now that I’ve thought about it, I’d suggest getting the Ramworks IIII from reactive micro with a RGB daughter card from A2Heaven. I beleive both come in either assembled or kit form

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Ah, right.  I see that now. 

Ah, right.  I see that now.  I actualy have a RAM Works III board, I didn't realize there was a modern replacement for the RGB option.  Thanks for the tip!

 

I like finding old Apple II cards, however.  There were so many unique ones produced...

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One thing I noticed about the

One thing I noticed about the a2heaven boards is that they offer RGBS.  I assume the S is a combined sync?  I think I recall most Apple RGB monitors of the day used that over separate sync, no?

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I know folks said it doesn't

I know folks said it doesn't apply to this scenario (and it doesn't) - but here is one of those "sidecar" splitters for the RamWorks RGB boards.  

Basically lets you use a RWIII RGB board with a non-RWIII aux memory card.  

https://www.tindie.com/products/lexington/ramworks-piggyback2/

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CT100 wrote:I know folks said
CT100 wrote:

I know folks said it doesn't apply to this scenario (and it doesn't) - but here is one of those "sidecar" splitters for the RamWorks RGB boards.  

Basically lets you use a RWIII RGB board with a non-RWIII aux memory card.  

https://www.tindie.com/products/lexington/ramworks-piggyback

It kinda does the opposite of what this guy needs.  I wonder if it would be possible to design a card which would allow you to use the memory from one card with the video out of the other.  I have some really hacky ideas on how maybe to do it...

Basically a slot splitter for the AUX that would allow selectively enabling and disabling signals which would let you figure out what was necessary to make the RAM work and what was needed for the video.  Still not sure if it would work, because I'm not sure how tightly coupled the functionality is on the cards.

 

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I was thinking maybe I could

I was thinking maybe I could use the RGB card in the slot  and then wire in the 64k aux ram directly to the motherboard behind a 74LS245.

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TimCross wrote:I was thinking
TimCross wrote:

I was thinking maybe I could use the RGB card in the slot  and then wire in the 64k aux ram directly to the motherboard behind a 74LS245.

I'd be interested to see how that would be done.  Where would you connect it and whatt would you do for hooking up the addressing and bank switch logic?  How to integrate the 2k that is on the RGB card with the additional 64k?

 

 

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Let's suppose there's an easier way...
TimCross wrote:

I was thinking maybe I could use the RGB card in the slot  and then wire in the 64k aux ram directly to the motherboard behind a 74LS245.

An LS245 bus transceiver is probably an unnecessary complication -- especially since you'd need to duplicate it for both DRAM banks in order to select between main and aux memory.

But let's suppose there's an (almost) trivial method: replace the motherboard 4164 chips with 41256 chips, and use pin 1 (A8) to switch between two 64K banks.  Most 256K chips are internally organized as 4 stacked 256x256 arrays so that the 64K DRAM refresh would be sufficient.  (Most //e and //c expansion cards exploit this feature.)

The minor complication is that some spoilsport at Apple connected pin 1 directly to +5v at the DRAM sockets, so you would either need to cut that trace at every DRAM socket...or just lift pin 1 out of each DRAM socket, connect them all together, and attach them to the CASEN* signal.

 

Ah, but there's a fatal flaw for 80-column mode: the video generator addresses both banks simultaneously, but the motherboard DRAM sockets just can't do that.  Even if we could somehow create a path to the second data latch, the entire RAS-CAS sequence would need to be performed twice for each video cycle to read a bit from each bank.  So programs like AppleWorks could run properly, but they wouldn't display properly.

 

Still, it sounds sufficiently feasible that I'd like to give it a try, just for the academic satisfaction of building a 128K Apple //e with an empty AUX slot.

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S.Elliott wrote:but there's a
S.Elliott wrote:
but there's a fatal flaw for 80-column mode: the video generator addresses both banks simultaneously, but the motherboard DRAM sockets just can't do that.

Oh, but an 80-column text card in the AUX slot might solve that problem.  It shouldn't even conflict with my hacked-in auxilliary memory, since the CPU would be writing the same values into that 1K region.  Double-hires would be distorted, but 80-column text would probably work just fine!

 

I've got to give it a try...if only to discover why it might or might-not work.

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S.Elliott wrote:S.Elliott
S.Elliott wrote:
S.Elliott wrote:
but there's a fatal flaw for 80-column mode: the video generator addresses both banks simultaneously, but the motherboard DRAM sockets just can't do that.

Oh, but an 80-column text card in the AUX slot might solve that problem.  It shouldn't even conflict wit

Fascinating! (said in Spock voice).

 

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