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TMS9918A Retro Video Chip Reimplemented In FPGA, With VGA Out

timothy posted more than 2 years ago | from the disintergrated dept.

Graphics 126

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.)

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126 comments

Um.... (0, Flamebait)

blcss (886739) | more than 2 years ago | (#39006975)

what for?

Re:Um.... (3, Insightful)

Samantha Wright (1324923) | more than 2 years ago | (#39006983)

For viewing things. VGA is somewhat nicer than the composite video out that most machines of the age shipped with.

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39006999)

With VGA and modern monitors, the graphics look like a bag of ass.

Re:Um.... (-1)

Anonymous Coward | more than 2 years ago | (#39007091)

What do you know about triangles!? Nothing! Triangles are a mystery to someone such as you! You will never understand triangles like I do!

I know everything about triangles now, mother fucker! Your true ferocity has been revealed to all!

Re:Um.... (1, Informative)

Grieviant (1598761) | more than 2 years ago | (#39007229)

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 [monoprice.com]

Re:Um.... (5, Informative)

Anonymous Coward | more than 2 years ago | (#39007329)

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.

Artifact colors (4, Informative)

tepples (727027) | more than 2 years ago | (#39007463)

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.

Re:Artifact colors (1)

tibit (1762298) | more than 2 years ago | (#39007881)

Arguably, this can be emulated. I don't know if this implementation does it, though.

Re:Artifact colors (1)

tepples (727027) | more than 2 years ago | (#39008637)

Arguably, this can be emulated.

And in fact, NES artifact colors have been emulated for a long time. The key is to emulate the way the original chip generated a composite video signal and then emulate a TV by decoding that back to RGB. But then that's the same thing as using the original chip with a composite-to-VGA adapter, unless of course you want to add the original CPU and I/O and put the whole console on the FPGA.

Re:Artifact colors (0)

Anonymous Coward | more than 2 years ago | (#39008789)

The majority of nes games still look better with a clean rgb signal though, even with the slightly different colors give by a playchoice 10 ppu.

I wish they'd do something like this for the nes, so less pc10s had to be sacrificed =S

Re:Artifact colors (1)

tepples (727027) | more than 2 years ago | (#39008903)

If you know Verilog, you could start writing your own NES-compatible PPU based on the detailed timing and behavior information on wiki.nesdev.com.

Re:Artifact colors (0)

Anonymous Coward | more than 2 years ago | (#39009921)

But what if you don't want the artifacts and you prefer the crisper look of straight VGA?

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39007465)

That depends highly on the internal resolution the device handles. While i'm sure there is some minor improvement, it's extremely unlikely to be a jump from 240p to 480p considering the hardware in question which was designed around composite. That said, this chip may do more then just simple output so it could very well look much better.

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39010321)

But... $100 more pretty?

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39010641)

And no, doing this after the signal has been produced at the composite outputs is not going to be as pretty.

It is actually going to be prettier. There is a reason to why emulators of the mentioned system have "composite emulation" and blur filters.
Sometimes throwing more pixels at it isn't a good solution.

Re:Um.... (1)

adolf (21054) | more than 2 years ago | (#39007521)

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.

Re:Um.... (1)

jellomizer (103300) | more than 2 years ago | (#39010383)

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.

Re:Um.... (0, Flamebait)

hairyfeet (841228) | more than 2 years ago | (#39007761)

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, we are talking consumer level quality of the early 80s, and THEN you are gonna have to take this working 30+ year old machine and take a soldering iron to it? Gee I wonder how this could go wrong......what are they nuts? It would be different if you were talking about a SoC to replace these system, maybe with some kind of universal adapter slot you could buy modules for for the carts and the controllers, THAT would make sense, but 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? I predict there are gonna be a LOT of "parting out" listings on eBay after this.

Re:Um.... (4, Interesting)

tibit (1762298) | more than 2 years ago | (#39007919)

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.

Re:Um.... (3, Informative)

Mr Z (6791) | more than 2 years ago | (#39008941)

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.

Re:Um.... (1)

tibit (1762298) | more than 2 years ago | (#39010071)

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.

Re:Um.... (3, Interesting)

anubi (640541) | more than 2 years ago | (#39009135)

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.

Re:Um.... (4, Insightful)

hairyfeet (841228) | more than 2 years ago | (#39009183)

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.

Re:Um.... (2, Interesting)

ogdenk (712300) | more than 2 years ago | (#39009421)

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.

Re:Um.... (1)

tibit (1762298) | more than 2 years ago | (#39010115)

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.

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39008429)

Yup, you're wrong. Anyone who can take a soldering iron to a modern motherboard to replace a cap is going to find the old consoles are knife & fork huge to work on.

And "damed fussy and temperamental"? Huh? For inexpensive stuff being bashed around as toys, this stuff had great reliability rates. Really not sure what you're going on about there.

Maybe you think this stuff is unreliable now because a lot of it now has dried out caps that need replacement? Or worn connectors? Examples, pls.

Disclaimer - I was a teen when this stuff hit. First thing I did with Coleco Combat was rip it apart to make different controller combinations.

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39008881)

This is quite old technology. You can fix with cheap, widely available tools. Probably get a few bad capacitors after all this time, but you could replace all of them for about $30 if you needed too. And do it without risking trashing the PCB, as it's all through-hole components, and the PCB tracks are big.

I'd never attempt soldering on something like an XBOX, that has surface mount components, and chips with hundreds of hidden contacts. I could probably teach you all the soldering skills required to fix a TI-99 in a couple of hours.

Re:Um.... (1)

drussell (132373) | more than 2 years ago | (#39009085)

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!

Re:Um.... (0)

50000BTU_barbecue (588132) | more than 2 years ago | (#39009709)

"Do you know how damned fussy and temperamental some of these machines were to start with?"

No, I don't Hairyfeet. Why don't you enlighten us? Name a few, and what was fussy and temperamental about them? And also please, define precisely what you meant by those terms. The computer not responding when you talk into the mouse doesn't count.

Re:Um.... (5, Insightful)

realityimpaired (1668397) | more than 2 years ago | (#39007021)

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.

Re:Um.... (0)

Anonymous Coward | more than 2 years ago | (#39007399)

This story is the most exiting thing I've read all day.

Re:Um.... (5, Informative)

kermidge (2221646) | more than 2 years ago | (#39007629)

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.

Re:Um.... (5, Insightful)

Mr Z (6791) | more than 2 years ago | (#39008981)

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.)

Re:Um.... (1)

kermidge (2221646) | more than 2 years ago | (#39009207)

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.

Re:Um.... (3, Informative)

rdebath (884132) | more than 2 years ago | (#39009931)

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.

Re:Um.... (1)

Narishma (822073) | more than 2 years ago | (#39010589)

He was talking about systems that used this particular VDP. None of those you mentioned did.

Implemented the wrong connector (2)

maroberts (15852) | more than 2 years ago | (#39007025)

he'd better do an HDMI version quick as VGA seems to be on the way out as a connector :-P

Re:Implemented the wrong connector (4, Informative)

0123456 (636235) | more than 2 years ago | (#39007071)

he'd better do an HDMI version quick as VGA seems to be on the way out as a connector :-P

Except HDMI is a closed standard and buying HDMI chips requires signing over your first-born to Satan.

Re:Implemented the wrong connector (5, Informative)

cb88 (1410145) | more than 2 years ago | (#39007133)

then just implement DVI-D over HDMI ... so you don't have to bother with the DRM. Check out the wikipedia article I imagine there are some kinks but HDMI is mostly backwards compatible with DVI-D And I have real world evidence as well.. Pandaboard does DVI-D for the very reasons you mentioned and it works just fine with a couple TV's I have tried that said it was picky one one monitor I tried though it seemed to be a kernel issue as one kernel would boot up on HDMI the other on DVI so had nothing to do with the hardware itself working correctly.

Re:Implemented the wrong connector (1)

windcask (1795642) | more than 2 years ago | (#39007345)

This sounds like a good plan. Most people are going to want to be playing these systems on their TVs, not computer monitors, and there aren't a ton of TVs still being manufactured with VGA-in.

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39007433)

Bought my 32inch last year and it has it. Calls it a PC port, which amuses me

Are you in Europe? (1, Interesting)

tepples (727027) | more than 2 years ago | (#39007489)

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.

Re:Implemented the wrong connector (5, Funny)

KiloByte (825081) | more than 2 years ago | (#39007339)

Except HDMI is a closed standard and buying HDMI chips requires signing over your first-born to Satan.

As someone who used to worship Satan as a kid (yeah, stupid), I resent that remark. Please do not insult Satan by comparing him to a vile media consortium.

Re:Implemented the wrong connector (2)

Anonymous Coward | more than 2 years ago | (#39007383)

Doesn't Lucifer actually mean "bearer of photoluminescence"?

Lightbearer = pirate = privateer. (0)

Anonymous Coward | more than 2 years ago | (#39008853)

Take note that Luciferianism and the Statue of Liberty are verry related,
as opposed to the Light.

Luciver is holding the Light, and is not the Light himself. Christ is the Light.

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39009443)

i knew there was a reason why i hated hdmi and preferred vga. i hate dvi also. i'll have to see if it is closed as well. i may have sixth-sense for open or closed...

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39009887)

I like DVI just fine, except for the mistake they made in using combined connectors for analog and digital.

It would have made much more sense to have adjacent ports with forked connectors at the end of the cable, so you could have an analog-only cable, digital-only cable, combined cable, or pairs of cables. Also an "extended" connector for dual-link that a single-link cable would fit into as well.

Re:Implemented the wrong connector (1)

K. S. Kyosuke (729550) | more than 2 years ago | (#39007453)

Except HDMI is a closed standard...

...that is freely downloadable from Chinese web sites... :]

Re:Implemented the wrong connector (3, Insightful)

0123456 (636235) | more than 2 years ago | (#39007817)

...that is freely downloadable from Chinese web sites... :]

Which is fine until you try selling a chip or distributing the plans, then the IP Barons come to beat you with a big stick.

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39007457)

...buying HDMI chips requires signing over your first-born to Satan.

Screw that! He can take my wife... please

Re:Implemented the wrong connector (1)

rthille (8526) | more than 2 years ago | (#39007637)

Satan (assuming he shows up to take him/her) is welcome to my first-born. I'm unlikely to have one, and wouldn't want it if I did. Now the woman actually pushing the baby out may have other ideas...

Re:Implemented the wrong connector (3, Insightful)

mattventura (1408229) | more than 2 years ago | (#39007077)

If they only had composite to begin with, anything above VGA is completely excessive. These machines are never going to be outputting 1080p.

Re:Implemented the wrong connector (4, Insightful)

Anonymous Coward | more than 2 years ago | (#39007187)

It not excessive. It's about supporting widely available monitors.

Re:Implemented the wrong connector (1)

Belial6 (794905) | more than 2 years ago | (#39008539)

No, DVI or HDMI will produce a vastly Superior picture to a VGA signal when you try to plug it into a monitor that only has HDMI inputs. VGA is counting it's last days.

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39009673)

I hope putting useless apostrophes into perfectly fine possessive pronouns is in "it is" last days too. And why the capital s for "superior"?

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39009389)

You haven't thought about the problem long enough, clearly. First of all, you are conflating the "format" of the video, with the "resolution". Second of all, maybe YOUR TV has composite inputs... mine does not.

Re:Implemented the wrong connector (1)

maxwell demon (590494) | more than 2 years ago | (#39007123)

Shouldn't adding a VGA to HDMI converter take care about that one?

Re:Implemented the wrong connector (1)

Joce640k (829181) | more than 2 years ago | (#39007469)

Missing the point: HDMI is all digital....and why should you need an add-on converter?

Re:Implemented the wrong connector (0)

Anonymous Coward | more than 2 years ago | (#39007617)

DVI can carry two signals: digital (DVI-D) and analogue VGA (DVI-A). A cheap DVI to VGA converter just connects to the VGA pins of the DVI connector. Since this device will only output DVI-D signals, a cheap converter won't work. Actual DVI-D to VGA converters are much more expensive.

Someone redo the C= 128 MOS 8563/8568 (4, Informative)

JoeCommodore (567479) | more than 2 years ago | (#39007069)

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.

Re:Someone redo the C= 128 MOS 8563/8568 (5, Informative)

Anonymous Coward | more than 2 years ago | (#39007527)

But this is not a big problem -- there's dead-simple passive analog circuits (e.g. [google.com] ) to do a passable conversion, and if you want to fix the dark-yellow/brown issue, that's not hard either.

RGBI signals in CGA are TTL, so converting to analog RGB is as simple as connecting them to the address lines of a suitable 8-bit PROM (or SRAM, in which case you'll want a battery to retain memory) programmed with appropriate RGB values, and three 2-bit ADCs on the output (0=0v, 3=0.7v for VGA).

You want to program the ROM/RAM as follows, assuming I as MSB (note color 6, brown, deviates from the expected 220):
N | RGB | xxRRGGBB
--+-----+---------
0 | 000 | 00000000
1 | 002 | 00000010
2 | 020 | 00001000
3 | 022 | 00001010
4 | 200 | 00100000
5 | 202 | 00100010
6 | 210 | 00100110
7 | 222 | 00101010
8 | 111 | 00010101
9 | 113 | 00010111
A | 131 | 00011101
B | 133 | 00011111
C | 311 | 00110101
D | 313 | 00110111
E | 331 | 00111101
F | 333 | 00111111

Or use a 16-bit ROM and wider DACs, and you could customize each color to exactly match your old 1902.

Seems a PCB with a preprogrammed ROM, DACs (could be as simple as R-2R ladder), and a scan doubler IC, should be much cheaper than a $100 replacement video chip.

Re:Someone redo the C= 128 MOS 8563/8568 (3, Informative)

mrmeval (662166) | more than 2 years ago | (#39008673)

That is cool.

I believe I saw one that did that and did not have the brown problem but it used a gal chip which most likely did the value change before being sent to a DAC. It was way more expensive than the solution listed which has more features as it was such a niche device. This was 1998-99 and was 350

It's a composite to RGBI to VGA converter. ;)
http://home.comcast.net/~kkrausnick/c128-vga/ [comcast.net]
This is pretty nifty and they have a workaround for the intensity problem. Price is now higher for the parts mentioned about 190. One of the companies listed has a dead website, dns problem maybe.

Here's another solution using and RGB to VGA and a resistor network to feed to the I input so that it's an RGBI to VGA converter. I think there's something wrong here but it works so it's not wrong.
http://sites.google.com/site/h2obsession/CBM/C128/rgbi-s-video [google.com]

Re:Someone redo the C= 128 MOS 8563/8568 (0)

Anonymous Coward | more than 2 years ago | (#39009397)

Yeah, that last one was the one I linked -- it gets the "brown" wrong (shows as dark yellow), but it's just so ridiculously easy.

Inconceivable! (3, Funny)

Guppy06 (410832) | more than 2 years ago | (#39007333)

classic computer systems such as the ColecoVision

This word, "computer," I do not think it means what you think it means...

/former Adam owner

Re:Inconceivable! (0)

Anonymous Coward | more than 2 years ago | (#39007397)

know you were trying to be funny. But most consoles are computers. Even those crap pong things they used to sell in the 70s... Just not very good ones by today's standards

Re:Inconceivable! (0)

Anonymous Coward | more than 2 years ago | (#39008395)

Those pongs were discrete logic, they had no CPU, and weren't computers.

Re:Inconceivable! (0)

Anonymous Coward | more than 2 years ago | (#39009363)

So what you're trying to say is that you do not know what a computer is.

Re:Inconceivable! (0)

Anonymous Coward | more than 2 years ago | (#39007407)

classic computer systems such as the ColecoVision

This word, "computer," I do not think it means what you think it means...

/former Adam owner

It works in the ADAM as well since it has a whole Colecovision board inside. My ADAM was the test subject for this chip (along with my SpectraVideo 318 and Tomy Tutor).

I don't have VGA (1)

dangle (1381879) | more than 2 years ago | (#39007537)

I have ColecoVision and a black and white TV.

Atari 800 in FPGA (1)

Doc Ruby (173196) | more than 2 years ago | (#39007699)

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?

Re:Atari 800 in FPGA (1)

JoeCommodore (567479) | more than 2 years ago | (#39007943)

Most home computers have analog circuits too - most notably for reading paddle controls, which FPGA's cant handle. And yes, folks do use paddles (also applies to some mice, and mini tablets like the Koalapad.

Re:Atari 800 in FPGA (1)

John Bresnahan (638668) | more than 2 years ago | (#39008121)

Most home computers have analog circuits too - most notably for reading paddle controls, which FPGA's cant handle. And yes, folks do use paddles (also applies to some mice, and mini tablets like the Koalapad.

OK, a FPGA and a 555 timer chip.

Re:Atari 800 in FPGA (1)

Osgeld (1900440) | more than 2 years ago | (#39008381)

everyone except the tandy series used a 555 timer based circuit for paddle and analog joystick control, nevermind its trivial to do analog even in 1980

Re:Atari 800 in FPGA (0)

Anonymous Coward | more than 2 years ago | (#39008525)

its trivial to do analog

Parent may have taken Logic Design course at school but isn't actually an electrical engineer.

Re:Atari 800 in FPGA (1)

JoeCommodore (567479) | more than 2 years ago | (#39009077)

Not an electrical engineer... I guess for that matter many hardware emulation designers aren't either as paddle support is sorely lacking from most game/computer on a chip/FPGA emulation units. :-/

Re:Atari 800 in FPGA (0)

Anonymous Coward | more than 2 years ago | (#39009573)

Your home computer's CPU "can't handle" analog in the same way that FPGAs can't.

More surpirsing than that... (1)

hal2814 (725639) | more than 2 years ago | (#39007733)

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.

Re:More surpirsing than that... (2)

MikeBabcock (65886) | more than 2 years ago | (#39007865)

I loved my TI99/4A ... I still have it somewhere. I didn't realize there was an active group for it, but its still an awfully advanced system for its era.

Re:More surpirsing than that... (1)

drussell (132373) | more than 2 years ago | (#39008995)

Yes, it was.. Real 16-bit even, though only the stock 256 byte system RAM (yes people, 256 BYTES) is on the 16 bit bus, but it's SRAM and runs at full processor speed (like L1 cache in todays processors)... I have an extra 32K of ram installed on one of mine directly on the 16-bit system bus... That would have cost a fortune back then, now it's just a few chips from the junk box! :)

Re:More surpirsing than that... (2)

Mr Z (6791) | more than 2 years ago | (#39009121)

Did you disable the wait states for the extra 32K RAM? I seem to recall that it did an address decode, and if the access was to the 8-bit bus and not to the VDP, it threw in a ton of wait states.

Re:More surpirsing than that... (2)

drussell (132373) | more than 2 years ago | (#39008957)

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 must not have had a PEB... With the Peripheral Expansion Box the 99/4A was capable of similar performance to the early PCs.

Even more surprising than that: There's an active TI-99/4A group? Really?

Yes, there are those of us still active in various old computer projects, building IDE disk interfaces, etc. to allow easy use of these fun old boxen.... I've built my own CROM/GROM emulator for the TI (someone else designed an IDE interface but I haven't built one for myself yet) and I'm currently designing and building an IDE disk interface for the old WANG 2200 minicomputer line...

Sweet! (0)

Anonymous Coward | more than 2 years ago | (#39007903)

Great, $100 to relive the magic of shitty hardware with no games. You know, instead of using an emulator to play the games on literally anything, with enhanced visuals created through post-processing techniques.

TI99/4a, how I miss thee. (1)

Beelzebud (1361137) | more than 2 years ago | (#39008311)

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. :(

Re:TI99/4a, how I miss thee. (0)

Anonymous Coward | more than 2 years ago | (#39008585)

You'll be surprised how cheap they can still be found on eBay.

Re:TI99/4a, how I miss thee. (1)

Beelzebud (1361137) | more than 2 years ago | (#39008743)

Oh man why did you have to do that? LOL I can see where some disposable income is heading in the near future.

Re:TI99/4a, how I miss thee. (1)

drussell (132373) | more than 2 years ago | (#39008985)

Yes, I don't have my original either (parents threw it away long ago without my knowledge) but I have 3 I picked up on eBay for a song... Go get one and a Munch Man cartridge and have fun... :)

The ColecoVision didnt use a 9918A (1)

Osgeld (1900440) | more than 2 years ago | (#39008371)

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.

Re:The ColecoVision didnt use a 9918A (0)

Anonymous Coward | more than 2 years ago | (#39008517)

I'd guess it's because the European ColecoVision had a SCART port, with RGB out.

Re:The ColecoVision didnt use a 9918A (3, Interesting)

Mr Z (6791) | more than 2 years ago | (#39009003)

It's not really RGB output, but rather Y, Y - R and Y - B luma/color difference signals -- actually frightfully close to S-video. But I'm pretty sure they had an app note back in the day that showed how to sum those to get RGB almost trivially.

The reason they went with the 9928A (and later 9128A) was to avoid the "rainbow effect" that was is prominent on the 9918A. See, the 9918A didn't flip the chroma carrier field-to-field, which leads to reinforcing chroma errors. That's also why you couldn't use the EXT VIDEO input on the 9918A to mix with arbitrary video sources (say, for a video overlay), but you could use it to daisy-chain VDPs to get more sprites and such.

Re:The ColecoVision didnt use a 9918A (1)

drussell (132373) | more than 2 years ago | (#39009273)

This board also replaces the TMS9928:

"The F18A is a pin-compatible replacement for the TMS9918A, 9928, and 9929 Video Data Processors"

Re:The ColecoVision didnt use a 9918A (0)

Osgeld (1900440) | more than 2 years ago | (#39009337)

thanks captain obvious

Uh.... (0)

Anonymous Coward | more than 2 years ago | (#39008491)

You could just buy a NTSC->VGA box on eBay for less with the added bonuses that you don't need to dig around an old computer and you can use it for anything else...

Re:Uh.... (2)

Osgeld (1900440) | more than 2 years ago | (#39009721)

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

Now all I need is a retro-cassette tape player (1)

mrshermanoaks (921067) | more than 2 years ago | (#39008897)

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.

AHA! Can fix my 99/4A! (1)

drussell (132373) | more than 2 years ago | (#39008937)

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

Re:AHA! Can fix my 99/4A! (1)

Osgeld (1900440) | more than 2 years ago | (#39009725)

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

Re:AHA! Can fix my 99/4A! (1)

drussell (132373) | more than 2 years ago | (#39009937)

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.

If you think THAT's cool...check this out... (3, Interesting)

ogdenk (712300) | more than 2 years ago | (#39009433)

http://spiflash.org/block/15.html [spiflash.org]

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.

It's more than just a video chip replacement. (0)

Anonymous Coward | more than 2 years ago | (#39009811)

The F18A also incorporates the 16K of video RAM as used by most systems using the TMS-9918A. It's also a drop in replacement for for the TMS-9929A which was the PAL version with component output used in most European versions of the TI-99/4A and other computers and game consoles using a TI video chip.

The pins for the original chip's video out aren't used on the F18A so the original composite or component video out doesn't work with one of these. The video out is VGA direct from the F18A.

But wait, there's more! With the F18A using an FPGA, it can be much much more than a totally stock copy of the original TI chip. Things like no 4 sprites on a line limitation, 80 column text modes and the big thing everyone who ever used a TI or other computer with these chips wanted, a true bitmap mode with every pixel individually addressable*. I don't know how much of that or other features are or will be implemented by the time the F18A is in production. I do know that such extended functions won't be available to pre-existing software without changing its code, though there may be a way to toggle the sprite limit.

As for it using VGA output, there's no shortage of old CRT monitors laying about in basements, garages, closets etc. There's also a plentiful supply of flatscreen TVs and monitors with a VGA input. I doubt many people will be plugging their TI, MSX or Coleco into a giant screen so they can bask in the glow of half inch pixels.

*That was the biggest 'fail' of those TI VDP's. The best they could do was chunking the screen into 8 pixel wide by 1 pixel high strips, where each strip could be any two of the 16 (15 plus transparent) colors. Doing that would have required more RAM, which in the 80's was extremely more expensive than just a few years later. Stealing and smuggling RAM chips in the 80's was big business.

We can go all the way back to 1840 (0)

retroworks (652802) | more than 2 years ago | (#39010311)

from wikipedia 2012.02.12 'Planned Obsolescence'

In Democracy in America (1840), Alexis de Tocqueville noted the rise of planned obsolescence in the United States: "I accost an American sailor, and I inquire why the ships of his country are built so as to last but for a short time; he answers without hesitation that the art of navigation is every day making such rapid progress, that the finest vessel would become almost useless if it lasted beyond a certain number of years."

Now I deal in used VGA and SVGA displays (exported about 30,000 to Egypt between 2002 and 2008) and I know there is a much longer reuse value for things than Best Buy or WalMart may have us believe. But there is a finite time between when the Model T is upgraded as a primary vehicle, and when it is upgraded for a Sunday antique show. The latter market tends not to want new upgraded parts (the 'original condition' has more collector value). So this invention will either A) be used by a very small market which wants to keep upgrading their gear for typical current use (e.g. Hollywood period film which doesn't care for historical accuracy but needs high display), , or B) used by Original Manufacturers to design upgradeability for changes in market demand. I think (A) is much more likely than (B), see "Planned Obsolescence". All that said, applause and hurrahs to Matthew H. at Atari, we are better off rewarding those who strive against planned obsolescence, despite de Tocqueville's sailor's advice.

Meanwhile, back in real time, Intel has stopped producing VGA outputs, and the display device market will stop making VGA devices, keeping chop shops like mine in business in the interim. http://www.pcauthority.com.au/News/241144,intel-announces-the-end-of-vga.aspx [pcauthority.com.au]

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