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TMS9918A Retro Video Chip Reimplemented In FPGA, With VGA Out
acadiel writes "Matthew H from the AtariAge.com TI-99/4A forum has finalized a design of a TMS 9918A replacement (with VGA out) for classic computer systems such as the ColecoVision, TI-99/4A, SpectraVision, MSX1, SpectraVision 128, and Tomy Tutor Home computers. This hardware project replaces the native video controller on these classic systems and enables them to have VGA output for the first time." (It's just under $100 to order one.)
For viewing things. VGA is somewhat nicer than the composite video out that most machines of the age shipped with.
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there's actually quite a community for these old systems, and a lot of people who don't enjoy playing on emulators, or who want to recapture the original experience.
it's pretty cool that they've managed to do this, though I might prefer a different connection type... my current TV does have a VGA input, but I doubt my next one will.
he'd better do an HDMI version quick as VGA seems to be on the way out as a connector :-P
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
Of all the chips that one on the Commodore 128/128D is a pain to convert to anything modern as it uses the old CGA/RGBI interface. All the CGA adapters ive found dont handle the intensity signal, they are more RGBA compatible.
"Enjoy what you're doing! If it becomes drudgery, you're doing it wrong!" - Jim Butterfield
Except when you can get a composite to VGA converter for 30% of the price of this chip.
http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10114&cs_id=1011407&p_id=4722&seq=1&format=2
Except that you're still upconverting a signal from 240p to 480p. By going directly to VGA you're at least getting a crisp 480p image (ie: 640x480). And no, doing this after the signal has been produced at the composite outputs is not going to be as pretty.
classic computer systems such as the ColecoVision
This word, "computer," I do not think it means what you think it means...
/former Adam owner
And no, doing this after the signal has been produced at the composite outputs is not going to be as pretty.
Unless you're using a program that relies on the artifacts in a particular video chip's composite output. The NES PPU's architecture was heavily inspired by the TMS9918, and I know a lot of NES games rely on interactions between luma and chroma to give the backgrounds more texture.
there aren't a ton of TVs still being manufactured with VGA-in.
Just about every LCD TV that I've seen in (U.S.) stores has a VGA input. It might be the case that you live in Europe and your local TVs include a SCART port instead. I'd bet the actual video processor in such TVs can sync to both 480i SCART and 480p-1080p VGA.
Except the question is not "how to make something work that can display this old machine on a new monitor," but "how to make this old machine have the best video output possible."
Composite video is inherently ugly, and was especially so on consumer electronics back then.
Replacing the video output chip with a custom part that outputs VGA directly eliminates all of the ugly that is composite video; putting a $30 Monoprice adapter in-line does not.
Kid-proof tablet..
I have ColecoVision and a black and white TV.
Better, perhaps, to ask "for whom?"
Please consider that just thirty-odd years ago, one could own a computer that wasn't the university's or corporation's. Whether one came fresh to it or from mainframe milieu, there was an immediacy, a power, a whole new realm of discovery. One no longer had to submit their deck of cards to an acolyte to the high priests of a Burroughs or CDC Behemoth only to get back a core dump due to an errant comma. Some, even now, for reasons of nostalgia or fun, continue their interest and enthusiasm - vibrant 8-bit micro communities are but a search away.
The TI-99/4A offered, amongst other things, 16 sprites with built-in collision detection. At the time this was nigh magical. Sprites were effectively independent of screen - they were a 'floating' layer above it and allowed for some interesting game and simulation possibilities. SCREEN itself was a defined device; one could PEEK and POKE 'most anywhere, and PUT and GET to any device. An entire screen could be represented with a string in memory, its contents readily changed on the fly. One could read data for a string from a DATA statement in program code or from (eventually) floppy; with several strings screen-swapping, almost animation, could be done. Graphics could accompany text adventures. Add sprites? Oh, my. And now with VGA?
You may have to ask "what for?" - others will not.
Why not put the entire Atari 800 in FPGA, in a PC, and use SVGA (and higher) output? That sounds like a really fun turn that "classics emulation" could take.
Are Atari computer game ROMs and software binaries still copyright restricted?
--
make install -not war
Even more surprising than that: There's an active TI-99/4A group? Really? Is Bill Cosby a member? That was my first home computer and so it'll always have that special place in my memories, but that thing wasn't very useful when it was still current. I can't imagine trying to do anything useful with it now.
You're completely, absolutely, out of you mind deluded. Sorry. At work I use some test instruments, made by Tektronix and HP, where the date codes on chips are all in the 70s. They work beautifully, and I regularly "hack" on them. They are anywhere between 30 to 40 years old at this point. There's nothing fussy and temperamental about those systems, and some of them are so complex that a consumer-grade microcomputer or game console holds no candle to them. I'd say that all of the consumer systems that this chip replacement would go into are comparably simple. If you would really have a problem with them, then it's your problem, not a general one. If you want complex, take any modern PC and try replacing a BGA chip in it. I'd take a 30 year old piece of gear any day, I probably could do chip swaps in those blindfolded.
A successful API design takes a mixture of software design and pedagogy.
My first PC was a TI 99/4a. I really really wish I had kept it. It's probably in a landfill somewhere by now. :(
it used a TMS9928A, hand over your nerd card now!
ok its the same chip just with RGB output though the Coleco didnt use RGB, which has really confused me, most of the computers use the 18 which spits out compostite, where RGB would be preferred, the Coleco used an RGB chip and summed it together into composite, talk about ass backwards.
If only I can find all my old TI-99/4A tapes, I can play my old Pac-Mac knockoff.
I'm tired just thinking about it, and bored already.
Heh! Perfect! I have three TI-99/4A machines and one has only B&W output because the 9918 is frizzafrazzed.. This will let me "upgrade" that one to VGA output! Sweet... lol
Probably the biggest problem is going to be all the old school electrolytic capacitors. I know my TI-99/4A is a bit flaky, and I suspect that's why. The VDP was running at the edge of process technology in those days (5.37MHz!) and it wants nice, clean clocks and nice clean supply rails. The rest of the machine runs a fair bit slower, with possible exception of the 256 byte SRAM that the TMS9900 CPU stores its "registers" in.
Thankfully, those big old electrolytic cans are easy to spot and easy to solder in replacements for.
Program Intellivision!
Actually, it was 32 sprites, with a limit of 4 to a line. It had collision detection but it was rarely useful. It had a single bit to tell you that any sprite hit any other sprite. To figure out what hit what, you'd have to walk the descriptor list and do the actual computation yourself. (Or, in the case of TI Extended BASIC, the interpreter had to do it for you.)
On the TI-99/4A, that meant actually accessing VDP memory, since there wasn't much other RAM in the system. That itself was pretty slow, because it wasn't memory mapped for the CPU. You have to write to the VDP's address register, and then do repeated reads after it fetched the byte. Depending on the display mode, that could be as long as 8us during active display (Graphics II mode -- everybody's favorite "bitmap" mode.). Fortunately, the address pointer auto-incremented, so if you were accessing a contiguous structure like the sprite descriptor list, at least you didn't have to keep reloading the address.
Not that TI Extended BASIC was necessarily able to do that, of course. (Read up on the abomination that was GPL. Not the license, but the interpreted language that much TI software was written in, including TI BASIC.) But if you wrote your own assembly code, you could make that optimization, which is probably how Parsec was able to do its soft-scrolling in the time allotted.
(Actually, VDP RAM isn't memory mapped on any platform that I know of. But other systems have CPU-addressable memory that you could store a shadow copy of data in at least. The paltry 256 bytes on the TI-99/4A, though, are far from enough in many cases.)
Program Intellivision!
A matter of perspective, I guess?
Let me see if I have this straight, feel free to correct me if I'm wrong. You first having to have a working one of these machines
Yes. Personally, I have three...
we are talking consumer level quality of the early 80s
Yes. One of mine has no color output, only B&W because the 9918 is fried... :)
Thus, I intend to get one of these chips and make that one into a VGA-out unit. Neat!
The chip is even socketed from the factory on the 99/4a (unlike the monster double-wide 64-pin DIP CPU), you don't even need to desolder it. If I remember right there's even a little aluminum heatsink on it attaching it to the chassis. It really was a pretty powerful little chip in it's day for the cost.
THEN you are gonna have to take this working 30+ year old machine and take a soldering iron to it?
Yes. That's how you fix and/or upgrade hardware things.
you are gonna take a soldering iron to a 30+ year old unit that its frankly a fricking miracle most of these things work at all? Do you know how damned fussy and temperamental some of these machines were to start with?
Yes. However, most problems with these systems can be easily fixed with proper use of said soldering iron. :)
They're actually very reliable!
Yes. I regularly "hack" my old stuff.
Fer cryin' out loud, they even gave me schematics!
I guess in those days they figured if you were knowledgeable enough to buy their thing, by golly you probably had the skills to fix it too.
It was TEST equipment, meaning you were connecting it to God knows what, where only God knew what malfunctions were in it. This is a sure-fire recipe for an occasional fireworks display on the bench.
Those were the days. I am glad I didn't miss them.
I learned more from fixing my test equipment than I ever learned from books and exams. And I got to learn from the best... Tektronix and Hewlett-Packard.
Like you pointed out, the BGA ( even those surface-mount IC's ) did it in for me. I could not get test prods on them, much less remove/replace them, even if I could get my hands on what soon became custom ASIC's.
The new stuff is either factory-support or downright disposables.
Those were the days. Thanks for another trip down memory lane.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
I'm sorry you apparently fail at reading comprehension so allow me to break it down. What you have was NOT consumer crap, what you have was designed for business and engineering which had waaaaay better quality parts. the caps and chips used in CONSUMER grade crap was then as now simply not up to the quality of professional instruments which is why we have workstations and desktops with the desktops having significantly lower quality caps, PSUs,fans etc.
We're talking about stuff built for kids in the early 80s and you are talking about HP back when they were THE scientific brand, I'm sorry pal but you couldn't be any more off base if you actually tried and those that marked you interesting obviously don't know how big a quality difference there was between HP and brands like Coleco whose other claim to fame was fricking cabbage patch dolls.
ACs don't waste your time replying, your posts are never seen by me.
Thanks, not only for correcting my paltry memory, but also for the clarification and further exposition. Had I mod points, you'd get some.
It was my brother-in-law's TI; I didn't spend much time with it, rather my own Atari 800. On that, I really never got down into the hardware, but did manage a few things during vertical and horizontal blank interrupts. The more heavy-duty technical aspects of all that stuff, then and even more so now, is way over my head.
I have an Atari 400 made in 1980, an Atari 600XL made in '83 and a 130XE made in '85. Along with a desktop DEC MicroVAX of mid-80's vintage. All still work just fine with no flakiness. Clean the cartridge ports and take care of them they'll outlive you. The 8-bits may have been low cost but they were QUITE well engineered. At least the Atari machines and Commodores were great. Not sure about TI or Coleco.
They made much higher quality caps then and used lead solder and much thicker PCB's with more copper. Later 80's 8-bits took a quality nosedive but they still weren't that bad, just had cheaper keyboards and thinner case plastics. The Amiga and ST were the major contenders by then.
Now if you want to see shitty caps, look at late 90's, early 2000's PC motherboards. I don't know too many 600mhz-1GHz Pentium III and Athlon desktop boards still running.
In general I find older 80's hardware much more tolerant of being repaired when necessary and with only 16 address and 8 data lines, hand soldering in modifications is relatively simple and lots of well documented hacks exist complete with code and schematics. I've added 512K, dual OS ROMs, S-Video and an IDE interface to my 600XL and it took about 45 minutes with a cheap radioshack iron and manual desoldering iron/pump. Try that on a microscopic ARM with 200 pins crammed into a BGA the size of your pinky nail attached to a 6-layer board.
http://spiflash.org/block/15.html
The VBXE video board for Atari 8-bit XL and XE machines. Will do 15khz RGB and VGA out and coexists with and extends the original video coprocessor chips (ANTIC and GTIA) providing a blitter and extending the color palette. Enhanced sprites too and more stuff. The Atari graphics chipset was much more programmable and flexible than this thing though every machine deserves to still have modern video output options. The Atari 8-bit is kinda like a baby Amiga in ways.
uh if you have ever used one of these shitty chi-co video samplers you would find the video quality was worse than plugging the composite signal into the antenna input of a 1977 black and white portable
you know recycled stock of these things come up all the time for less than 10 bucks, the only advantage here is the monitor bandwidth if they didnt fuck up their sampling, which is very easy to do
Actually, VDP RAM isn't memory mapped on any platform that I know of. But other systems have CPU-addressable memory that you could store a shadow copy of data in at least. The paltry 256 bytes on the TI-99/4A, though, are far from enough in many cases.
On the contrary, many 8-bits had memory mapped video. Commodore (VIC/64/Amiga), Sinclair (Spectrum, zx81, zx80, dist by Timex in the US) Atari, VT100 ... etc etc. Not that there weren't machines with distinct video RAM, the Commodore PET had specific video memory, though it was still mapped into the address space like a modern PC video card. Having the video RAM in a inaccessible (I/O bus) location was rare.
The reason was simple, at that point in time only a relatively small amount of RAM was needed for the machines and it ended up being faster than the CPU. So much so that you could assign 50% of the RAM bandwidth to the video subsystem without impacting the speed of the processor at all.
The ZX81, however, was a bit of a foreshadowing of things to come. It was built really, really, cheaply and they used really cheap DRAM. This cheap RAM wasn't fast enough to feed both the CPU and the video at the same time so the CPU was basically turned off when the video was being displayed (In fact it was physically used as a counter chip by the ultra cheap video controller).
Nowadays people want astronomical quantities of RAM so it basically has to be the cheapest design possible; this type of RAM can't keep up with just one CPU, let alone multiple CPUs and a video controller. So the video controller has to reduce the performance of the main CPUs by stealing cycles, or it gets it's own RAM.
Note: There are several Intel video controllers for PC clones that use main memory as the video RAM, they get added as a cheap motherboard video controller. Because of the fact that they're using slow RAM and stealing cycles from the CPU these are rightfully seen as very low performance.
On the other side, a common mistake for designs with distinct video RAM is that the CPU only ever needs to write to this RAM, unfortunately the problem is frequently only recognised in production.
you know recycled stock of these things come up all the time for less than 10 bucks
Oh, I know... I just never bothered because I have three 99/4As and it still works, just not color and could be useful for parts if one of the ones I actually play with (one is original, one is modded) have a problem. Now if I buy one of these, it's $10 saved by not buying a 9918. :) I had always thought of getting one of the later Yamaha chips like used in the Geneve, can do a little board for one of those with 128k or 192k of video RAM and do whatever it was, 512x512 graphics... I don't have a Myarc so always kinda wanted to play with one of those, but now I think I'll get one of these VGA-out boards for another option.
Electrolytic cans are one thing, another thing is probably the abysmal power distribution (long, winding tracks) and poor decoupling techniques. A 5MHz "clean" clock has useful harmonics up to about 50MHz, so a decoupling cap that's far away from all the circuit points where the clock goes/comes from may be useless -- and you have to measure along the traces, not as crow flies. When you design with general purpose electrolytic caps, you pretty much assume that for digital logic decoupling purposes they are open circuits above a couple hundred kHz. That's the only sane conservative assumption, unless you characterize the ESR of the parts you actually use (no substitutions!), and then test their behavior in final circuit.
A successful API design takes a mixture of software design and pedagogy.
Usually it's not about parts, but about quality of the design of the circuit (and parts, too, of course). It takes a whole lot of money to open a chip fab, no one will a-priori decide "hey, we're making a fab for poor quality chips!". A, say, 6502 or Z80 CPU used in one of those "consumer crap" devices is not graded for consumer crap (except for temperature range, and they avoid the use of the term "consumer crap"), it's the same one that went, at the time, into industrial and T&M equipment.
From my experience, the quality is almost always about design of the product, the individual components are rarely to blame for anything (with some notable exceptions -- IC sockets that don't use machined pins are almost universally crap, but we all learned that lesson quite well I presume). Sure, you'd argue that those consumer products were poorly designed, and I can't but agree in many cases, but that doesn't make them inherently finicky! If you have a poorly laid out board, it doesn't get worse over time, you know. Same goes for most any other poor design decision, unless it affects component longevity, and there the major issue is heat, and a minor but omnipresent issue is transients on signals due to poor board layout. Regular ICs and discrete semiconductors usually don't give a damn about heat as long as the die stays below 100C, same goes for many other discrete non-semiconductor parts. Only electrolytic capacitors are really an issue here, and perhaps PC board that gets hot enough to discolor -- usually from resistors that are too hot as designed (just my anecdotal experience).
Basically it goes like this: if there's a problem, you troubleshoot, figure it out, and fix it. It may be less enjoyable if the design was poor to begin with (Apple Time Capsule's baked PSU caps, I'm looking at you!), but just because it was from the 80s and was consumer grade does not make it somehow special simply due to its age! I'd say that an ABC-80 (a Swedish microcomputer) with its horrible socketed daughterboards for 80 column mode (I have a 25+ year old specimen) is not any different than the Time Capsule. Both had aspects that were improperly designed, and you address those deficiencies as you fix them - better connectors and stress reliefs for ABC-80, "forever" tantalum caps and a fan reorientation for the Time Capsule.
A successful API design takes a mixture of software design and pedagogy.
Composit video did have some neat hacks that is more difficult to produce today. There are emulators still trying to match the composit look.
First the low DPI of the tv made low resolution less pixelated all the pixels had round corners making low res images look softer.
Another cool hack was using particular color offset combinations to create colors beyond what the video card can support.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
He was talking about systems that used this particular VDP. None of those you mentioned did.
Mada mada dane.
Well we know now that the caps from the late 90s through mid 00s were crap due to industrial espionage where they stole only part of the formula and boned the recipe, but Atari before the Warner buyout (and for a year afterwards as they cleared out existing stock) frankly wasn't consumer grade quality, they actually put care and love into those. Compare them to someone like Coleco or Mattel who were toy companies that simply jumped on the electronics bandwagon and its night and day. With the Coleco you had both the Atari adapter and Adam PC plugin, both of which concentrated heat, and Mattel made good handheld in the 70s but their handhelds in the 80s like that one that took interchangeable carts (sorry i can't think of the name ATM, they had a Star trek game and breakout for it both of which I had) was really crap.
The ONLY real advantage I'd argue you had in the 80s were the boards were so primitive that replacing caps and other failed parts is easier simply because the boards are so big. Good luck replacing parts on a PS 1 or Xbox 1 or Dreamcast with those tiny boards and double sided chips. That's why i'm glad there seem to be emulators for just about all the machines (although the Xbox one is severally lacking) because most systems from the late 90s on up will frankly be unfixable. Like you said the odds of finding a late model P3 running are pretty slim, but surprisingly i'm find the P4 and early Athlon machines if they didn't get a batch of the bad caps are running like champs. I've got three of them sitting in the shop right now i need to slap on CL cheap, the 2.2GHz and up P4s and Athlons seem really hard to kill short of a lightning strike as long as they didn't get the bad caps. Some of them make great nettops BTW, the 1.8GHz Sempron I'm typing this on now surfs like a champ and is quiet as a churchmouse. Once i get those offlease sold I may just slap an ubercheap Athlon mobile in it just to cut power usage down even further.
ACs don't waste your time replying, your posts are never seen by me.
Narishma already said it here, but I was referring specifically to machines that used the TMS9918/28/29(A) VDP, often just referred to as "the VDP." So far as I know no system that uses the VDP was able to memory map and dynamically multiplex CPU and VDP access to the 4K or 16K of DRAM connected to it. And, that walled off access to the DRAM was a particular drawback for machines that used the VDP, which is why I pointed it out.
Program Intellivision!
And they will come in handy don't the road as they will still be 'unencumbered' .
---- Booth was a patriot ----
Actually the original PS1 isn't so bad, neither is the Dreamcast. I've worked on both. There's actually a fairly common issue with controller ports failing on the Dreamcast that's relatively easy to fix. The XBox and the 360 are nightmares.
It is quite possible to repair newer electronics using modern techniques with hot air reflow soldering and surface mount components. Techniques are different and with silver solder the melting point is closer to the failure point of components but it is still quite doable. You'll have better results repairing with leaded solder.
Generally though, aside from crappy 80's power supplies, most of the computing gear produced then is more reliable than today's gear. It may be slower but that doesn't mean they weren't cool designs. Hell the Atari 8-bits had programmable graphics hardware and could display 256 colors. A 6502 is also easier to understand, interface with and code for than a modern CPU so experimenting is easier. They also still make the 6502 and the 65816 pin-compatible 16-bit variant.
I find cheap $2 programmable microcontroller IC's and making my own PCB's more fun than PC's now. Getting into real electronics is easier and cheaper than ever these days.
Old P4's and Athlons really don't impress me much, yeah you can run linux on'em and put them to use but it's still a PC. I'm more interested in things like the Raspberry Pi these days which would probably spank most old P4 at 1080p video decoding with nothing more than passive cooling.
Electrolytic capacitors only fail very rarely. What you find is that disc ceramics fail and pull the +5V rails down (they go leaky, and there are dozens of them used to decouple supply rails), and tantalum beads just plain explode when they fail.
You might find that very very old electrolytics have dried out a bit and lost capacitance, but that should be obvious because the supply rail will ripple badly. Leaky disc ceramics will get warm.
Don't just blunder in and start ripping out capacitors without having some idea of what you're doing, though. I've scrapped too many lovely old synthesizers and radios because people go "HURR DURR IT NO WORK MUST BE CAPACITAR" and start "re-capping" and then bring it round when it now has way more faults than it did to begin with.
So, asking a valid question to clarify the OP's statements, with a cheap Star Trek reference thrown in is a "troll" around here now? No wonder I never post anymore.
Mostly random stuff.
Best video output possible? That sounds an awful lot like marketing department FUD unless the source resolution of the video signal is actually being increased. I'm sure it might be interesting for a few enthusiasts, but it seems awfully hard to justify the $100 price tag just for a format shift.
It's not a question of resolution or format shift, but of color. The chroma channel of composite NTSC video gets smeared all over the place by design, along with other issues (such as dot-crawl) that come with bad interlacing implementations -- especially with composite sync.
S-Video would help some of these problems without increasing resolution, but VGA does not have these problems at all, which is what makes it useful.
To be clear: It's into the realm of esoteria. But in this area of stuff, we also have people modifying Sega Genesis systems for improved video and sound, along with a lot of other stuff that would only interest a real enthusiast (of which you don't seem to be one -- neither am I).
Get back to your books, kid. I'm sure you'll be able to solve the rest of the world's little problems by dawn if you just continue to pretend that they simply don't exist.
Kid-proof tablet..
For the record, I have a 12 year old 450 Mhz PIII Dell desktop that continues to do duty as a network monitor, with 100% uptime except for reboots for software updates, and forgetting that it won't boot unless a keyboard is plugged into it.
I could replace it, but why? It's been perfect so far, and recently took an upgrade to 32 bit RHEL6 without a hitch.
I have no problem with your religion until you decide it's reason to deprive others of the truth.
While it is true that the Pi could probably make a hell of an HTPC frankly there just isn't that much more you can do with the thing, not unless you are an expert coder with intimate knowledge of assembly so you can squeeze every last drop of performance out of the chips. With that Athlon I can make an HTPC, nettop, file server, jukebox, firewall,workstation, hell depending on the board i can even slap a good cheap PCIe card into it and make it a render box for video transcoding, because of the generic nature of x86 and the abundance of code frankly its trivial to make it into just about anything. Hell if all you are wanting is a media tank I'd just pick up an Nbox HD, those are like $59 and it has all the major formats at 1080p and you can just plug a USB drive into it and call it a day. For the pi personally I think a better use would be a carputer where every single volt matters.
I figured the xbox would be a PITA as i looked at modding mine for a little while and looking at how tightly packed the board was figured it wasn't worth the PITA for an SD video tank. Honestly this is what i hate about the consoles, you have this hardware that COULD do other things but the whole DRM in a box nature of the things make them pretty much worthless for anything but playing approved games in the approved manner. that's why i have a PS1, Genesis, SegaCD, Gamecube, and SNES just sitting in a closet gathering dust. ironically the only console i have that still gets any use is the Dreamcast thanks to the pirates who figured out how to load third party code on the thing without hacking the hardware so the DC makes a great emulator box. I have all my old Genesis and SNES games on a DC disc so I can fire up the DC and enjoy some classic gaming with the boys anytime i want.
In the end that's why I'll always prefer the PC to console, you can always find a new use for the PC. My first gamer box, a 100MHz Pentium is still being used 5 days a week as a C&C controller for an $85,000 lathe that will only run on an ISA card, my frankenputer from 2000 ended up in the hands of Suzy the checkout girl who brought it to me to speed up not realizing I was the original owner, i slapped an old P4 CPU and board I had lying around and now that box is still going, letting her and her kids surf the net, and I'm able to take all these offlease office boxes i get from local businesses and refurb them so folks that wouldn't normally be able to afford a PC can have one. It feels good to help somebody while saving hardware from the dump, too bad it isn't likewise easy to find a new use for all these old consoles but it looks like especially with the first gen X360s these things are designed for the dump, but I wish you luck on your hacking but my old hands simply aren't steady enough to be messing with the solder anymore.
ACs don't waste your time replying, your posts are never seen by me.
Oh okay, I obviously didn't go far enough up the thread.
But that does make me wonder why people would be so enamoured with this chip, a video controller that can't (it appears) share the memory with some other DMA/CPU etc chip and forces all accesses to it's memory to be made through a 'pin hole' of a couple of I/O ports really strikes me as a bit of a deal killer whatever other features it might have.
Well, it did do a lot for you. And the large RAM with flexible descriptor tables meant that in practice, you could avoid doing too many writes over to the VDP most of the time. And, the separate dedicated-RAM architecture does guarantee no cycle stealing, unlike, say, the VIC and VIC-II chips in the Commodore computers, or the need to wait for horiz/vert refresh to avoid "sparkles" like the old CGAs.
Let's face it, all these old computers were an exercise in tradeoffs.
Program Intellivision!