cbmeeks

I am most definitely interested in one of these boards! Especially if the cost isn't too high. Great work!

I still haven't told the wife about my recent FG99 purchase. Or the TI-99/4A assembly language book. Or the two TI carts. Or the 25.175 MHz crystal oscillators (for a VGA/FPGA project). So I'm probably already in hot water with my purchases. But it will be soon. Just need to decide which I want more.

That's where I keep my hot tea warm. At the same time, I use my ColecoVision power supply as my ottoman.

Ah cool! I'm planning on ordering a TIPI or a NanoPEB from you sometime soon. When I do, I'll get some shells in there too. Thanks!

OK, the standard color codes for composite cables are yellow for video, red and white for audio. But, those are just standard. Nothing stopping anyone from building a cable with non-standard colors. From what you're telling me, it sounds like the yellow cable gives the black screen. You are plugging yellow to yellow on the TV right? TV's are more consistent with their coloring. Yellow on the TV is more than likely composite video. If you're still getting a black screen then it could be any number of issues. From a bad VDP to bad (cold) solder joints. Do you get any activity if you wiggle the cable on the back of the TI? Does the screen jump any then? Also, if you managed to take it apart....maybe you could post some pictures of the unit so we can take a look.

Ah, I didn't realize it's been exposed to outside elements. Yeah, if there are lots of rust and debris inside that thing, that could be a real issue. If the chips and pins aren't corroded, it's possible the fix will be easy. But other than cleaning it, you may need more tools to test conductivity, etc. Oh, I like the 8-Bit Guy, but I wouldn't take his teachings as the best way to do anything. He's a little too quick to retro-bright things IMHO and some of the technical information he gives is wrong. But he's entertaining at any rate. That "worst VIC-20" episode he did (along with the Osborne) makes my skin crawl the way he left them. :-)

Oh? Tell me more! So he owns the original molds? Is he making a batch of shells? Oh come on! It can't be that bad. LOL You're only making me want to play it more now. I just looked on eBay and they are actually quite pricey for a TI game.

My grandmother bought me my first computer (the TI) when I was 9. This would have been in 1982. She bought it from a Western Auto store. This particular store sold things like car parts, bicycles, etc. For some reason, they had some very cheap TI's there. Probably when TI was selling them for $49 or so. Western Auto went under a long time ago. Regarding Sears....I remember when Sears was THE place to go when you wanted to shop. That Christmas catalog was my internet in the 80's. I remember seeing a Porsche car in Sears as a kid. Not a full size. But a small, child-sized Porsche that ran on gas. Sort of like a go-cart but with a licensed Porsche body. I go into that exact same Sears today...and it's almost empty. They are literally selling the fixtures and furniture. Sad... K-Mart was where my mom bought my first NES games. And I used to see TI and C64 games there as well.

Funny, the C64 has always been my go-to winter computer. I load up the Christmas demo every year around Christmas time. Play some classic games, etc. For me, it's not the make/model of the winter computer that's important...it's the retro/nostalgia of using a vintage computer while sitting near the toasty heater that warms the soul. :-) Then again, I have a permanent spot in my office for vintage computers so I have one going all year round. Oh, and Parsec can get pretty fast sometimes. :-)

Danggit. I wished you hadn't told me that. Now I have to buy that game. I have sort of a weird addiction to collecting things that are crap. LMAO. Which explains why I have many of the games AVGN reviews.

Sorry if this is OT but I just had to tell someone. I'm a huge fan of CRT TV's. I still prefer them with my older consoles. But, they are getting hard to find. Whenever I see a small one that is cheap, I usually snag it. A while back, I found TWO Sony PVM's for $15 each at Goodwill. However, I didn't buy them!!!! I have no idea why I didn't. I'm kicking myself for it. I could have sold one and paid for both. A few months later I found yet another TWO CRT TV's. This time, they were normal CRT's. Except for one thing. They had to be 40" or more!! I kid you not. The most gigantic CRT's I've ever seen and they were NOT the projection kind. I didn't buy them because I literally could not lift them. Plus, would have nowhere to put them. Then came yesterday. I found another large (maybe 32") CRT from Sony. This one had an odd, curved shape to it. The screen was maybe 32" but the housing was much larger. But what really caught my eye was that it had TWO HDMI ports!!!! I didn't know any CRT TV supported HDMI. I really thought about getting it but again, no place to keep such a large TV. Have you had any odd CRT spottings?

I assume you are connecting this to a modern (LCD/Plasma) TV. If so, many of those TV's don't like the composite signal from older hardware like the TI. The fact you are getting a black screen (instead of the no-signal blue screen) tells me "something" is being sent to the TV and it's attempting to lock on. Without any testing equipment or a spare, confirmed working TI, to test, it's hard to determine the issue. So a few suggestions would be: 1) Try to locate the original RF modulator and skip composite. You may have to find an older (preferably CRT) TV to test it on. The picture will be fuzzy but should be legible. This will tell you if your composite cable is good and if the TI is OK. 2) Try to locate an older TV. Especially a CRT TV that has composite inputs. This will rule out your modern TV. 3) Finally, it might be worth sending it in to someone on the forums for some troubleshooting. I'm sure there are people in here that would be glad to help. I've had some hardware experience so I might be able to do it. But it would take me some time as I am currently moving my office downstairs and things are a mess right now. 4) Buy a working TI off eBay or CL. The good news is that TI's are still affordable and haven't skyrocketed in price like Apple's and Commodores. Keep us informed. It's awesome that you are trying to revive a TI for your boyfriend.

So...are these blank cases or something? I think I'm missing something here. Well, I didn't really want 3D printed. I've never seen anything that was 3D printed that didn't look and feel 3D printed. Like I said, 3D printing is a wonderful thing but it's not for me when it comes to cartridge shells.

@Klaus First of all, thanks so much for the very detailed explanation! That helped tremendously! >> Each Grom chip contains 6K of memory, even though the Grom memory map occupies 8K for each. What was the purpose of them being 6K? I assume they still were on some type of masked ROM chip from TI. Was the 6K limit artificial or hardware specific? >> Most cartridges, released by TI were written in Gpl and were a Grom only release. >> When speed was critical, it was a combination of Rom (speed) and Grom (costs, size). I assume the GROM chips were cheaper to produce. In a world where bytes cost more money, companies could save money by using the cheaper (although slower) GROM. A game like Tic-tact-toe didn't need expensive ROMS for speed. Correct? >> If you were a software company and wanted to release carts for TI-99, either you bought the full license, got access to the very restricted Gpl Documentation and software and were then able to order Groms to be >> produced by TI. Or you wrote your software in pure Tms9900 machine code, which was fully documented and you burned your Eproms on your own. TI didn't see a penny then. I can see the advantage of GROM. With RAM/ROM space being super expensive (relatively speaking) in 1979, GROM was a way to map more space in that narrow 8 KiB window that ROM carts were restricted to. Sort of like another cartridge inside the main cartridge. However, the benefits really dwindle when you factor in that you can only access this window through a small hole for the address and data. And with TI making the GPL code expensive and obscure, they really put the nails in that coffin. This is the kind of crap large mainframe companies (IBM) do...but at a micro level. :-) So now I wonder, in 2019 with all of the resources we have now, what is the need for GPL code in our titles? Seems like storing data in that area and just swapping it out is the thing to do. >> At one point TI only produced mainboards with an updated System Rom [v2.2] which removed the check for Rom headers when loading the Master selection screen. This means, a cartridge with only Roms will not >> show up on such a TI. This essentially locked out Atari games from being loaded. Wow. That is a dirty trick. LOL. So this means that only GPL games (which cost companies real money to license) would work in those machines. Shame on you TI. Are those v2.2 machines the "QI" boards I've heard about? >> Software companies started to use a cartridge schematic, where some controller made some of the Eproms appear as a Grom to the TI. >> This then even allowed 8K Groms instead of the usual 6K. By doing this, it now becomes possible to have huge amounts of banked out ROMS in that small "window" of GROM space? The TI and the cart thinks there is only 8K in ROM. But by using the port into GROM, you could switch out the GROM address and use traditional ROM for much more storage. Very clever. You would just need to copy the data from the GROM into somewhere accessible by the CPU. Would be convenient for holding things like tile maps and sprite data. So, I assume this port into GROM's address bus is 8 bits. Does that mean there can be 256 pages of 8 KiB for a total 2 MiB? This makes sense. Each page in the FG99's memory cannot directly access the other pages. So by placing data in the "global" 32K area, they can pass information to each other. Thanks everyone for their explanations! It's going to take me a few passes to get things down. I've spent most of my time learning the ins/outs of C64, Apple II and VIC-20. So this is quite a bit different than those worlds.

I hate sacrificing a legacy TI cartridge. I just bought TWO copies of a "boring" educational game. For one, I'm going to sacrifice the shell for my new FG99. The other will go into my collection untouched. What would be nice is to find some empty, newly produced cartridge shells for this sort of thing. Not to mention a way to build my own carts from the software I write. And before people start with the 3D printing....sorry....I'm just not a fan. 3D printing is amazing and has its place in the world, I just don't like it for things like cartridge shells, etc. I've recently been tinkering with the idea of doing my own injection molding. Might be fun to take a cart and make a silicon mold from it. But, obviously, if this has already been done, I'd rather buy some blanks. So, anyone know of a source for empty carts? Thanks!

But you wouldn't get access to all of the buttons. That's what I need. All buttons working.

Wow. That looks pretty awesome! How does it work? Well, if I did anything at all it would be so that any cheapo NES controller could be use on the TI. I've always hated that the Atari 2600 "standard" got carried over to so many platforms simply because it was there. C64, Amiga, etc. had such great graphics/sound that it's a shame they never had better controllers. So it's time for the TI to get good controllers. :-)

That doesn't sound very common. Does it have four buttons in addition to the directional pad? The NES basically had 8 bits to indicate the status of the controller. Four bits for the directions and four bits for the buttons.

I have a few small ideas on some boards I'd like to design for the TI-99/4A. Something simple at first while I learn TMS9900 assembly. One such idea is to build a board to convert the NES controller to something the TI could read. I know the NES uses a serial shift register and the TI (or something) would have to supply a clock, etc. to get the values out of the NES controller. I don't see a way for the TI to send an output pulse through the joystick controller. So my initial thought would be to connect a small ATTiny to the NES controller and constantly read the controller at maybe 30-60 times per second. Then, the micro-controller could send the parallel value to the joystick port. However, I didn't see anything in the pinout that could support this. I would need 4 signals for the directions and 4 for the buttons (A,B, Select, Start). The TI only supports one fire that I saw. Then I thought...what if I wrote a serial driver for the TI and just monitored the trigger button? Then serialize the NES controller stream over that. I would need some clever way to sync the devices, however. What are your thoughts? With 32K of RAM, an F18A (and a possible soundcard I want to build), the TI is shaping up to be a killer gaming system that deserves a good controller. BTW, I love the Genesis controller and perhaps it would be easier...but I'm after the NES controller.

OK, maybe I'm a thousand miles off on this...but please let me know if I have this right. The FlashROM 99 (FR99) could only work with binary files and not true "cartridges". Even though it plugs into the cartridge port. These binary files are simply loaded into the stock 16K of an unmodified '99 and/or they could be loaded into the 32K Sidecar RAM as well. Real cartridges you bought back in the day contained some ROM and/or GROM. The ROM on these carts usually stored the actual machine code the game/app ran. The CPU ran this code directly. The GROM of the cartridge contained graphics and, IIRC, some proprietary graphics language (can't remember what it's called). So, getting back to the FinalGROM 99 (FG99), the 512K RAM chip on that card is used to emulate ROM and/or GROM depending on what cartridge you loaded from SD. Is that correct? Furthermore, I've read about GRAM and RAM being on some carts (can't remember which) that the CPU could write to but not directly like RAM. I believe it had to go through the VDP?? If so, does the FG99 support that as well? Sorry for the detailed questions. I'm really trying to understand how the TI works at a hardware level. I want to start asm programming for it and building some cards. Oh, and I just purchased a FG99 so hopefully that will arrive sometime soon. :-) Thanks!

Ah, then I guess I'm confused on the 512K of RAM on the FG99. What is that for? Thanks!

I have (and love) the 32K sidecar for my '99. I also have the FlashROM 99. I'm wanting to buy the FinalGROM 99 and read that it also has RAM expansion. So my question is, will I still need the 32K Sidecar if I get the FinalGROM 99? If I use them both, do I get the 512K from FG99 and an additional 32K from the Sidecar? I'm still trying to understand how the TI maps all of this memory (GROM still confuses me...lol). Thanks!

Thanks for the information! @FarmerPotato, it sounds like you are nearing a new sound card? An idea I had was to make some type of small audio card that would sit between the TI and the speech module so that it could pass audio through from the speech. Not sure how that would work. As much as I love the TMS9919, I was thinking of using the YM3812 and maybe a CPLD for glue. Plus a DAC. But I'm curious about your FORTI-2. I've tried Forth more times that I care to admit and I just can't wrap my head around it. I'm more of a 6502/ASM coder. Do you have more information on your project?

So, I was wondering...is it possible for a TI cartridge to have an additional audio chip like the Famicom games did? I found a cartridge pinout but didn't see any pins for audio. But I vaguely remember someone connecting a SID chip to a TI a long time ago. Was that through the side expansion? Finally, does anyone know why some type of audio expansion (other than speech) hasn't caught on like the F18a? The beauty of the F18a is that it's a standard as well as enhanced video. Seems like something for audio would be desirable as well. I've recently designed my own 6502 computer (and had boards made) so I guess I'm looking for an excuse to start a new project. :-) Thanks

Lets say I have a stack of 8K and 32K EEPROMS. If I match the pinouts, can I make my own CV carts or do I need some other logic in between? Which brings me to my second question, how are /8000, /A000, etc. used on the CV? Would my cartridge have to set those somehow like with pull up/down resistors? Im learning more about the CV hardware so please excuse my ignorance. Thanks.