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schuwalker

Anybody else a 'Collector' of the TI-99 4/A?

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I'm looking for information on burning a EPROMS to work on an actual TI99 system... Most roms are not 8K but need to be 8K to work with the multicart projects I have found on the web. I don't understand why almost all .BIN files I see are some strange file sizes like 12K, or 7K...

 

My first question is, why are all the sizes for game binaries so strange? Sholdn't they all be a multiple of 2K/4K/8K/ect.?

For example, I have 3 roms images: Bonkers.bin(6K), Brain.bin(5K), and Camelot.bin(11K) that I want to burn to an EPROM and play on an actual TI99. Is this just not possible?

 

My 2nd question is: What steps do you take to use these 5K or 7K files to create an 8K file to work with the 64/128/512 multicart projects?

 

I have a good understanding of the Atari 2600 bankswitching and burning of ROMS/EPROMS challenges but, that same knowledge does not seem to translate well to the TI99.

 

What am I not understanding here?

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There are multiple answers to your question, due to the fact that the TI has TWO different types of chips used in its cartridges. The first is the vanilla ROM chip you are used to. The multicart boards require you to place each ROM within an 8K space and a menu program to access them if you are using more than a single 8K block. That menu has to be in the first 8K to ensure the computer comes up in it (although, since the 74LS379 used here doesn't have a "forced" initial state, we usually put the menu in the first and last banks to ensure it works every time). The second part is a bit hairier: TI used a proprietary memory chip called a GROM. GROMs are addressed on 8K boundaries, but they generally only hold 6K of data. They do not occupy processor memory space, they are addressed as devices, with their own, internal 13-bit address bus. Reading the GROM causes that address bus to auto-increment to the next byte of data. These are your real problem children, because you only have a limited number of options here. You can use a GRAM device (there are many flavors of these) to contain the programs and run them (they simulate a GROM environment in RAM), or you can use a GROM emulator (like the 512K module that I've been working in with Acadiel and Tursi). your 6K files are almost certainly GROM files, while your 7K and 8K files are almost certainly ROMs. Note that a cartridge may have BOTH types of memory. A standard cartridge can contain up to 5 GROM chips (equates to 30K) and up to four ROM banks (though only one original cartridge from TI used four ROM banks--TI Calc). Nothing used more than four ROM banks until the 64K cartridge boards came out, although the Superspace boards from DataBioTics were apparently capable of being modified to do so.

 

Are your three files capable of executing from cartridge space in emulation? If yes, then you should just need to burn each one into an 8K space (although Camelot is a bit odd and may not work unless it is intended to use 2 banks as programmed). You'll need a menu program if you burn a larger EPROM (look at the TI section under classic computers here on AtariAge and there is one attached to one of the cartridge board threads). Note also that the TI is backwards from other systems you've used--what you think of as A0 is A15 on the TI (using 16-bit addresses) and D0 is D7 (cartridge space uses an 8-bit data bus and reads two addresses (even and odd) to get a full word for the CPU to work with). I hope this helps.

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Good evening folks,

 

I recently came across a lot of several hundred Atari/Intellivision/Coleco/TRS-80 games, and I'm going through them and I notice one TI-99 4/A game among them.

 

It's called Garbage Belly, and it appears to be complete with the box, manual, registration card and game casette. The box itself is in pretty solid shape, though the artwork is starting to fade - however everything inside the box is pristine. There isn't any artwork on the casette itself - it just looks like someone typed on a generic label and slapped one on each side. Does anyone know any history on it and/or the worth? I'm rather unfamiliar with TI-99 stuff.

 

Thanks!

Edited by Donnicton

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Moonbeam Software. Their programs are not particualrly rare, but they seem to sell well on eBay. Prices range from a low of around $10 to a high of around $25 or so when there are regular bidders looking for one. I've seen them go higher, but not often.

 

Other Moonbeam Titles: Death Drones and Robot Runner. I have all of these and one or two more that I bought back when they were new products.

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I might get into the TI 99 but mostly just for Tunnels of Doom. Which I now own. I am not sure if I will collect for it or just be happy owning that one game though.

 

As is I am into enough systems already and TI is pretty easily emulated and files easily procured. I don't know yet. Sadly finding computers locally is a tough one.

It is mostly just consoles in any retro shops.

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I haven't seen an emulator that does the TI justice. Especially the voice synthesizer.

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I haven't seen an emulator that does the TI justice. Especially the voice synthesizer.

 

Maybe it is due to having not played on a real TI since the 80s but the emulator I messed around with was pretty darned good. Plus you know, being able to use 360 controllers or my Genesis 6 button with a RetroUSB dongle.

But I rarely see some of the issues a lot of authentic only folks do sooo..

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I haven't seen an emulator that does the TI justice. Especially the voice synthesizer.

 

Have you looked lately? IMO Classic99 does the 99/4A a lot of justice. As for speech, well, it is not well emulated *anywhere* for any platform. Custom audio chips like that are incredibly hard to emulate with software. Speech on the 99/4A was usually a trivial afterthought in most software anyway, and not missed very much if you didn't have the speech synth.

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