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VideoCart - VS23S010 cartridge


Matej
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I like XEP80 idea. So what about cheap video graphics card in form of external cartridge?

There is nice chip VLSI VS23S010 made in Finland. My idea is to have 20usd cartridge with TV composite cinch.

 

Homepage:

https://www.vlsi.fi

 

Webshop:

https://webstore.vlsi.fi/epages/vlsi.mobile/en_GB/?ObjectPath=/Shops/2015020901/Products/"VS23S010D-L+%28Tray%29.+Integrated+Circuit%2C+Country+of+Origin%3A+KR%2C+Taric%3A+85423190"&Locale=en_GB

 

Datasheet:

http://www.vlsi.fi/fileadmin/datasheets/vs23s010.pdf

 

Forum:

www.vsdsp-forum.com

 

 

What it can do???

256-color text and graphics at resolutions from 160x200 up to 460x224 (PAL: 508x240) pixels

 

Software sprites (up to 32 sprites sized up to 32x32 pixels).

 

Scrollable tiled background graphics engine with up to four layers.

 

320x192 x 65536!!!

 

So on ATARI monitor out you will have map, life, weapons and game will be on second TV (videocart). Or game will detect videocart and there will be 160x200 x 256 colors instead of 4 or 16...

 

I can imagine 508x240 GUI! Picture viewer... Also amazing text editor or asm, disk commander, basic language or text game...

 

It will not rival build in Atari graphics chip or VBXE. It will be more like addon or second graphics card (like on PC).

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post-35094-0-76084000-1530131021.png

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Edited by Matej
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2 problems with external graphics addons:

 

- interface speed and methodology. A SIO or controller port based adapter is just too slow for graphics. OK for text operations and if it can do automous stuff like scrolling then it can be liveable. If cart based with memory mapped IO and able to address the graphics RAM directly then is should be good.

 

- yet another standard. There's XEP80 among other legacy addons and there's VBXE in the modern day. VBXE as it is doesn't have widespread support. Yet another graphics adaptor just spreads already thin resources even thinner.

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This is a weird video display chip. It is essentially a direct-mapped YUV bitmap display chip with an oddly flexible microcode for selecting bitfields and a display list engine on top of that, along with a simple rect blitter on the side. It has no sprite engine, no palette registers, no tile/character lookup, and no masking or shifting on the blitter. So you can display really nice bitmaps, but anything moderately complex will bitmap manipulation, which will be well beyond the 6502's abilities at a reasonable frame rate.

 

If someone does come up with a cart like this, put flash ROM or a pass-through on the cart. One of the problems with Veronica is that it takes up the cart slot but has no flash of its own, so in order to get code onto it you have to push it through another interface like disk or SIO, which is slow and awkward. It's a lot more interesting if you can boot the computer and pull the necessary code+data to use the cart from the same cart.

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- yet another standard. There's XEP80 among other legacy addons and there's VBXE in the modern day. VBXE as it is doesn't have widespread support. Yet another graphics adaptor just spreads already thin resources even thinner.

 

IMHO this *is* the most important argument against such a solution: After more then 10 years (!) of VBXE the count of games etc. supporting VBXE is a very manageable amount.

 

XEP80 was only a character-based serial attached solution, which was cool stuff in the 80s, but from a today´s view... very lame. To use such a videochip Matej mentioned it must be realised as a buss solution (PBI / ECI) with a lot of supporting chips to make it useful, fast and give added value. Then the final price will be in the range of VBXE - or above, when a nice case is applied etc.

 

At the end it´s the same question like using VBXE, Rapidus and so on... if you want to have graphics and speed doubled or more than a stock Atari XL/XE, take an Amiga ;)

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Hello Jürgen

 

After more then 10 years (!) of VBXE the count of games etc. supporting VBXE is a very manageable amount.

 

The VBXE has one problem: You have to solder it in. To a lot of people that's a problem. But (almost) everybody can plug in a cartridge. No matter if that's a (single) game cartridge, a flashrom cartridge or a video cartridge.

 

At the end it´s the same question like using VBXE, Rapidus and so on... if you want to have graphics and speed doubled or more than a stock Atari XL/XE, take an Amiga ;)

 

If you want an Atari with a memory extension, get an XE, not some plug-in memory extension. Or get an ST or Amiga.

If you want an Atari XL or XE, buy an Atari XL or XE, not an Incognito-Board for your 800.

...

 

Sincerely

 

Mathy

Edited by Mathy
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I'm doing something a bit similar to this. Read the part starting with "Hang on, what was that last thing ? Video ?" about half way down.

 

Basically, there's one of two modes - either Atari-native or new video modes.

 

Atari Native:

This is actually the harder part - you monitor the bus for activity that corresponds to video-related transactions - eg: Antic reading the display list vector, Antic asserting /HALT and transferring character/bitmap data, the CPU changing colour registers in DLI's etc. You then reconstruct the display based on the same information that Antic has. That video display is placed in the frame buffer of the chip, and clocked out to a video display via an HDMI chip. I'll probably run the display at 32-bit colour (including alpha-masking for sprites), 640x480 (so pixels are doubled) at 60Hz.

 

New video modes:

This is actually easier - you just set up the video display on-chip and tell it to go. Writing to the frame-buffer (probably double-buffered to prevent 'tear') is then done through trap-style calls to the 6502's memory map. Blits are handled with the DMA2D engine in the chip, and sprites are available by writing to the overlay plane. Resolution depends on colour-depth, we could get 800x600 in 24-bit colour, DMA2D enabled, 2-layers for sprites etc. Or if you just want a simple picture, set it up in CLUT (colour-lookup-table) mode for 256 colors at 1920x1080. You get to trade off resolution for colour depth and refresh rate as you see fit.

 

To try and make the video display "more standard", I'm including it as a component on the motherboard, not as an add-in card. The chip that provides the video also provides USB and Ethernet, so it's a 3-for-1. There's also 32MB of graphics RAM, and 32MB of system RAM added in as well, so graphics sprites can have the space they need to be stored.

 

And this just plugs in the back as well - I'm working with the ECI on the XE at the moment, but I don't see why this won't work with the XL parallel bus, and possibly even a replacement CPU card interface in the venerable '800... It's actually designed to be cross-platform, not just flexible within the Atari range of computers.

 

The board is undergoing design review as I type (and the first results have come back with some recommendations for improvements which I'm implementing). It might seem that there's no activity in the web-postings, but if you look at the GitHub repository you can see there's been steady work on it for quite a while now.

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My 2cents...

 

I recently picked up VBXE coding again...

 

The issue i have with video boards.... you need a fast cpu to drive the board. The 1,79 6502 is not honestly.

 

Best combination so far is the Atari Lynx where its 6502 is clocked 4 MHz and the frame buffer size plus blitter speed seems to be well balanced.

 

But standard 1,79 MHz filling a 64k vga buffer of a VBXE is a heavy task. Sure thats where is blitter is coming in place but blitter needs data, too.

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