LCD/VGA Interface in the Apple II

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stynx's picture
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Hi all,

im researching a shr VGA/LCD solution for the Apple //e and IIgs. Since the VOC has demonstrated the possibility of SHR in the Apple //e and as there is a Carte Blanch bitstream for SHR available, i have looked deeper into the matter. My results with the CarteBlanche are not as promising as i thought. A powerful display-solution needs more memory than the 2x128k Sram on the CarteBlanche. The other problem is, that the CB is very rare (only 50 were ever produced) and will never be a mass-product.

Either way, i have found some nice LCD-Controller that feature 24/16/8-bit interfaces, and 6800/8080 compatibility (3.3V though).
SSD1963: 'intelligent' Frame-buffer
RA8875: enhanced Graphics LCD Controller

Both controllers allow up to 800x480px resolution and offer up to 16bit (RA8875) and 24bit (SSD1963) color.
The RA8875 has several Text-modes, supports graphics-functions and allows DMA (and BitBLT) functions with an external Flash of up to 16mb.
The SSD1963 has a direct 24bit interface, that can be configured for use with a 8bit-bus. This Chip does not have any graphics or text-Functions but offers some Bitmap-modes.
Both ICs need a color (tripple) DAC or DVI-converter and can as well be directly attached to a LCD.

I want to test these ICs with the CB and try some stuff i have in mind.
My goal is an advanced Apple II graphics solution, that can display all Apple II modes natively and offer some alternate modes as well.
The interfacing should work with memory-mapping (up to 640x200x2) and direct access (up to 800x480x16). The interlaced VOC-Modes might be interesting as well.
Im really just a beginner in verilog and VHDL... there might be a bit of a delay Wink

Any thoughts?

-Jonas

AttachmentSize
RA8875_DS_V12_Eng.pdf4.27 MB
SSD1963.pdf1.69 MB
ra8875 app note.pdf471.7 KB
PB30Prototyping.pdf2.27 MB

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stynx's picture
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Re: LCD/VGA Interface in the Apple II

I just got Info about the RA8876 Display Controller. It will be available this year and offer some nice improvements over the RA8875. Especially the high resolution (2048x2048) and multi buffers display are really nice.

MarkO's picture
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Re: LCD/VGA Interface in the Apple II

One year ago I was looking at the PICASO for doing Apple ][ to VGA/DVI/HDMI Interfacing..

This is a definite area that needs to be explored..

MarkO

stynx's picture
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Re: LCD/VGA Interface in the Apple II

I looked into the Picasso as well. The limitations of the chip took it out of the equation Wink Im more or less set to use the RA8875/6 because these controllers support the needed resolution as well as some neat drawing functions... I hope to be able to begin development with the 8875 and switch to the 8876 later. There are other chips from epson but these are much more complex to interface (16/32 bit data- and 22bit address-interface for example).

A solution with only the Carte Blanche seems to get too complex since more memory is needed as well as extensive programming for realizing fully buffered true color virtual displays. No solution is perfect Tongue

-Joans

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Re: LCD/VGA Interface in the Apple II

I don't quite understand why you would need a lot of memory if you're only gonna do Apple IIe graphics anyway? Wouldn't the Carte Blanche's memory be enough?

I made a VGA adapter for my Apple II using an old Xess Corp. XSA-50 FPGA board. It is not fully buffered though; it generates the VGA signal on the fly, so it only needs to keep a copy of the Apple's graphics memory. It supports all native modes, and uses a character map in the on-board Flash memory (I copied the character map by hand since the CPU cannot access it).

I have been thinking about designing a PCB and send for manufacturing, but I'm not sure I would be able to sell it at a reasonable price...

speedyG's picture
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Re: LCD/VGA Interface in the Apple II
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the second part includes less friends but a lot more joy on life....

stynx's picture
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Re: LCD/VGA Interface in the Apple II

Quote:

HDMI-VGA-Video-Adapter-for-Apple-II ...

Its just a video-converter. The quality tends to be very different from model to model. I did not intend to just display composite onto a tft but to have the ability to natively display the video memory contents onto a modern display. These should include SHR, that is only possible with the VOC or CarteBlanche (SecondSight?) right now...

My goal is a complete downwards compatible graphics solution for the Apple II (Slot-based).

To reach that, i will make some proto-boards for the CarteBlanche using the SSD1963 and the RA8875 as well as a palette-DAC for comparison.

-Jonas

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Re: LCD/VGA Interface in the Apple II

The NTSC video gives the more saturated vivid and live colors and effects that no RGB or other card achieves on my opinion. Of course, GS graphics looks awful on NTSC...I see no sense in bulding video cards nowadays. Once upon a time it was hard to get NTSC monitors in some countries. Now many cheap (and contemporary) TV sets have composite or RGB inputs and work nicely and all have the digitizing (LCD tvs) dedicated computers built-in that do the job of these ridiculously expensive video converters sold on ebay for instance...

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Re: LCD/VGA Interface in the Apple II

I left commenting just to see the reactions....
anyhow after this 2 postings some few remarks....

In fact when arguments will bring the task ahead ( or not ) here some of them:

Take the double hires availiable at the IIe or the next higher resolultion at the IIGS are still
only halfsize of VGA standard.... ever thought about the requested memory for storing this resolution ?
Of course will be the reply... and my question again : really ???

How many adressinglines will be requested for such resolution ? ahaa... here we get close to the point...
regular Applesoft is only able to deal with the maximum of 2 byte handling in video and most if not
nearly all software only supporting such resolution...

and keeping in the backyard of the mind the demand for the refresh of the screens...
i guess a picture with high resolution but only flickering at half of the cycling time will be rather disappointing...
of course your correct - the modern chips will be able to handle faster refresh and duty cycles of the extracted videomemory on specially allocated memory area offside of the CPU Memory area...

but how much time will be requested for change to new graphics from CPU area to Video area
and with how many cycles.... ?

In fact a 6502 will only be able to handle a partial area of a VGA output within acceptable time...
and it will request a lot of shape creating similar machinecoding to handle that demands...
it won´t create stunning rather fast movements like it was possible by direct adressing mode within the CPU accessable memory of the Apple itself...
it´s rather more just able to handle higher resolutions of picture scans or simple drawings without complex motion...
so back again to the aim of my question:
what shall be the aim/target for the use of the higher resolution ?
a better picture projection on new monitors or for creation of new games that might support the higher screen resoltions ?
And does anybody really believe this to work fine also on Apple IIe ?
Or shall it just be restricted to the IIGS only
( which allready supports rather higher resolutions due to it´s advanced adressing modes )?

My intention by this questions is just to kick ahead the explenation of the targets of such project and getting a dispute about reasonable aims and limitation definitions within such project...
sincerely speedyG

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the second part includes less friends but a lot more joy on life....

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Re: LCD/VGA Interface in the Apple II

You are quite off-topic. It doesn't matter how slow is 6502 in drawing graphics or moreover the applesoft basic which is hardly used for that purpose... With a page select "soft" switch one can "instantly" switch video output to an already prepared graphics page. This topic I guess is about displaying the apple's video output on a contemporary display...

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Re: LCD/VGA Interface in the Apple II

At Kansasfest this year there will be a session:

"•Off-the-grid Total Portability for the Apple IIc (Steven Buggie)"

This ebay auction describes what he will be presenting:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221447214363

I submitted the question on the bottom of the auction.

Now if you were to add this product into the mix:

http://www.amazon.com/Archer-Audio-Signal-Enhancer-15-1955A/dp/B002NL5SYW

You would probably get the brightest video from an apple //e possible.

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Re: LCD/VGA Interface in the Apple II

I really don't get the skepticism about an advanced Apple II video-Interface. I have a CarteBlanche sitting in my Apple IIe that is perfectly capable to display all video-modes the non GS Apple II is capable of. It displays the 256-Color SHR modes as well... on an Apple IIe.
The CarteBlanche has two major flaws, that make it highly problematic to advance the project:
1. Memory: The Carte Blanche has 256k of 8bit wide 15ns sram. I need much more memory that have to be a bit wider or faster.
2. No onboard 12bit Video-DAC: The onboard resistor-based Video-DAC only has 6bits

Solution:
- Better Verilog programming (needs skills and a lot of time, that i don't have)
- external hardware like a graphics chip, Ramdac, ... fairly 'easy' and offers new high-resolution graphics modes.

I have a Proto-Board for the CarteBlanche that i intend to use for:
- 1mb external Sram (55ns 8bit) as parameter memory
- RA8875 Graphics Chip with embedded Video-Memory and graphics/character modes
- 16mb serial-flasch connected to the RA8875 for additional memory (through RA8875 only)
- 24 bit Video-DAC (connected directly to the RA8875 in 16 bit mode)

All this is just to replace the Video-generation in the FPGA. I had some troubles generating a stable VGA-output on my CarteBlanche (500-modell)
If the Verilog code can be reduced, a smaller FPGA (or even a CLPD) could be used for the emulation/conversion of the Apple-Modes.

It might be very interesting to offer the advanced video-modes of the RA8875 directly to the Apple II as well as emulating the original Apple II (gs) modes...

-Jonas

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Re: LCD/VGA Interface in the Apple II

The main question is what software would use your new video modes. Therefore it is meaningless to make new video modes. For already made vintage software there are many perfect solutions and displays to enjoy the picture. Why make it complex???

stynx's picture
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Re: LCD/VGA Interface in the Apple II

Quote:

Why make it complex???

because it is possible?

Why was there a SecondSight? Why is this piece of hardware so much sought after? Why do people buy the component AUX-card from nishida-radio for the apple IIe? Why do people invest time in the Apple II anyway?

My answers:
It would be nice to have a 640x400 mode on the IIgs (VOC interlaced without the flicker). Picture viewers would be relatively easy to do on any Apple II. A patch for Basic for faster line-darawing and so on is not extremely complicated either.
...
This hobby is not about the why should i bother, but rather why do i invest time in old junk hardware anyway Wink
My impression is that a Apple II with nice crisp colors and a flatscreen as well as all the native IIgs modes would be a cool thing to have.

-Jonas

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Re: LCD/VGA Interface in the Apple II

They do that because of ignorance. (I would have used a more eloquent word). And a few because of nostalgia, curiosity and very few because of reversing challenges and disliking apple company policy of selling overpriced cheap hardware to ignorant clients for years Wink

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Re: LCD/VGA Interface in the Apple II

Quote:

They do that because of ignorance.

Interesting point of view...

Is using a CFFA 3000 ignorant as well?

I like to use CRTs more than a TFT but CRTs are getting more sparse as time goes on. My CRTs are too precious to me to be used up. Try to get a CRT (the tube) repaired when its burned in ... . For that reason i want to have a good alternative to the CRT that does not look like shit. VGA CRTs are still widely available and offer a similar experience to the non-VGA CRTs. I like the sound of a DISK II as well, but i use the CFFA 3000 more and more because im lazy and the features of the CFFA save a lot of time.

I have a big problem with the RGB converters for the IIgs since the 640x200 mode gets all shitty on a TFT/Digital TV. (i tried 3 different chipsets of converters)
An older line doubler might be able to offer a similar quality to the native 15kHz video-mode onto a VGA-CRT.

Anyways ... i will continue to get the card done Wink .. In the meantime i have to wait until the needed chips arrive.

I might continue working on the AFL-MC16 clone since John Ridges said that he would send me the MC16 Software Laughing out loud

-Jonas

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Re: LCD/VGA Interface in the Apple II

Has anyone tried one of these?
http://www.sabrent.com/category/tv-video-capture/TV-LCDHR/

They are currently on sale at Fry's for $25.

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Re: LCD/VGA Interface in the Apple II

Since the Apple II NTSC signal is not completely NTSC compliant, you will get mixed results with a composite to vga adapter like that one.

My suggestion is that if you want VGA from your apple ii, then you can get a Koichi's component and 80 column ram adapter cards and a Gonbes converter.

http://tulip-house.ddo.jp/DIGITAL/A2ECOMP/english.html

http://tulip-house.ddo.jp/DIGITAL/A2ERAM/english.html

http://arcadeforge.net/Scaler-and-Strike-Devices/cga2vga-Scaler-PCB::13.html