jdgabbard

Thanks Ksarul, it's possible I suppose. I'll shoot you a message when I get to the office.

Oh the joy of not understanding what you're doing... Ok, so here is where I'm at. I have one of the black Fetzner boards. I have it populated with all of the components, sockets, and a seated 74LS379. The only thing that is different is that I used a 10nf cap as opposed to a 1nf cap. I seriously doubt capacitance is of major concern here, it's essentially decoupling the LS379 from what I can tell. I do have both the 2.2k resistors in plave. The burner I'm using is a PCB50, which was hell to get working on win7. I am having a few issues with my blank checks returning false negatives. It'll say it is t blank when in fact it is. The EPROMs I'm attempting to use are M27C512s, and I get an programming error when attempting to use the 27C512, but using the 27512 option they program and verify fine. But here is the problem. I've decided I don't know as much about the way this works as I thought. I've tried the 64k roms from the hexbus site. It works, but only has one option. Some chicken game... Even with the two (optional?)swutches wired it apparently only reads that one bank. And the further complicate my position, I've tried several other 64k carts that were in a thread on the forum, and none of those worked. Anyone care draw this out in crayons for me?

Well, whatever it is, it doesn't appear the 9900 is initializing. This is where I wish that scopes were cheaper, because it could be as simple as the 3mhz crystal being dead. But without being able to do any probing with a scope I'm guessing.

Well, I got home and turned on the TI, and sure enough, it doesn't boot. Maybe the video ram or chip... It makes a sound similar to what my other system does when the nanoPEB isn't plugged into 5v power just like I said earlier... Like to the video is below. Anyone have any ideas? The good news is all the cartridges tested good, as well as the speech synthesizer. So I did get a working unit as far as that is concerned... http://youtu.be/g-UI9qAcxR0

Don't you hate it when you think to yourself 'Man, I should have bought that...'

Disregard

Yeah, I was shocked he let everything go so cheap. He told me that he is more of a console guy, so he just wasn't too interested in it, or want to devote the time to it. They also had a lot of atari stuff in there... So colovision too..

Was visiting some friends in the city I used to live in and stopped by a Retro Gaming shop. After browsing for a few minutes I asked a guy who was replacing capacitors on an old Game Gear if they had any TI Carts. He came from around from behind the counter and asked if I meant the 99/4a, then pointed me to a couple of carts. He then asked if I wanted a Speach Synthesizer. I asked if it worked, and he said he didn't know, he didn't have a working system to test it on. I asked how much and he told me $12, and said they had a 30 return policy, so if it didn't work to bring it back.. I said sure. Then he asked if I wanted a parts system for $5. I asked him what was wrong with it, and he said that it just made a weird noise when he turned it on. which sounds exactly like what happens when I turn on my system without plugging in the power cable for my nanoPEB. Which leads me to suspect the 7805 had possibly gone bad. I don't know for sure, but I snatched it up too. Along with the 5 cartridges that he sold me for $8. So for $25 I got a system I think I can get working (no cables or power supply), a Speach synthesizer that I suspect works, doesn't look like it's ever been plugged into a system but maybe once, and 5 carts. Of which Blasto and Personal Record keeping are the most desireable. But I did also get two Terminal Emulator carts. So overall, it's been a good day!

Never had a 99 growing up. We had a C64 that was off limits. Finally sometime around 93-94 the old man got a IBM-Compatible machine at the house that we were allowed to mess with. Ended up buying a 99/4a a while back, and I recently purchased a second to begin duty as a loaner to a fellow coder.

Just acquired a second TI-99/4a that I'm trying to breath life back into. This unit is going as a loner to a fellow coder for collaboration purposes on a few projects. However, it is missing the power and A/V cables. Obviously I can't use mine since this is going to be located at a separate location, and I don't have any spares. Does anyone have a set of spares that they'd let go for a decent price?

Thats awesome man. I wish my old man would have got me playing around with stuff like this when I was his age. Rather I got the classic "Hey! Thats not a toy!!!" line that most kids got.

I've got this model as well, although, I do not have a F18A. I will say this, external power in my experience is mandatory, otherwise you just get a black screen and a loud tone from the audio.

unebonnevie, I've already spoken with Ksarul off-thread. And he has expressed his permission to port it over to eagle. As for opening it with Eagle, eagle cannot open ExpressPCB files. So it is something that I'll have to do manually. Ksarul has even been generous enough to offer some templates for the PCB, which I may take him up on when I get my plate open enough to sit down and work on this. After having talked to him for a while through PM, I feel convinced that he and I would have EPIC nerd-out sessions if we ever found ourselves in proximity.

Ksarul, sorry man. I didn't mean to step on any toes. I had noticed you made the ExpressPCB file and the Gerbers available to the community, and had no intent to profit from it in any way. I knew you had various different projects that you had worked on, but also didn't realize that you did this as a means to fund future projects. My intent was to simply make it easy for the guys who are so inclined to have a at-home solution for a cart without reinventing the wheel. Simply make available what you had already done in a different format. Never to steal your idea or design, or profit from it for that matter. I don't use RobotRoom, and havent used ExpressPCB for the obvious reason (you're limited on what you can do with it). Similar to if this was done in, say, Fritzing. Some people use it. I don't because it doesn't suit my individual needs. What I am saying is, I understand where your from coming from. And I do respect you and your work, reading about the work you guys have done has been a lot of fun. And if your wish is for this not to be converted into an Eagle *.brd file, I will withdraw my ambition. And I hope you'll accept my sincere apology. I just assumed with the files being posted on the forum that modifications were allowed as long as credit was given.

Man, talk about a heck of a deal!

Sweet. I have a XB cart, and the Nano, so I guess I'm set as far as actual hardware. However, I'd probably use it on the PC with C99 to be honest. Mostly because I can copy and paste large portions of code from a text document into the terminal. But I'll take a look at it this afternoon.

unebonnevie, I'm planning on doing a port of Ksarul's board over to eagle when I get a moment. I really just need to sit down and figure out the schematic and layout. Which might change with minor variations as far as the *.brd file is concerned. That would really help with the DIY guys like myself who would rather etch a board at the house than to order them from ExpressPCB or someone who did order them from the PCB house. Not to mention open up a few other places to order the boards which are far cheaper than ExpressPCB. However, if you decide to jump on that before I get a chance, feel free to PM me, and I'll help with testing the new board layout. I have all the stuff to etch and burn the EPROM. Not to mention a small hoard of components. The schematic will be the hardest part, really. Not because it's a difficult schematic, but just because I've got to sit down and trace where all the traces go. I'm planning on doing that once I get done testing the PCB I'm building for a quad-bot I've got underway. Once that is tested I'll be getting it off to one of the pcb houses, and I'll plan on starting to work on the port to eagle.

Thanks. It was inspired by the comments above. Falcon, This is the first I've hear of XB256. Is this a cartridge similar to XB, or just an addon? Just for emulation on C99 or is it something that is available for the actual hardware? I've been playing with CALL PATTERN. I think my algorithm is off, as I cant seem to get it do much of anything. I'm going to keep playing with it, and see what I can work up. At this point I'm just working on the physics. Scrolling maps is another issue that I'm going to eventually have to address, as I think that is going to use up a ton of memory. I have a NanoPEB, which if I'm not mistaken has the 32k memory. So that may not be so crucial. However, I'd like to no have to rely on that if possible. I will say this, BASIC might be more difficult to learn than C...

Out of curiosity, and mostly because I hate to start another thread just to ask a question, how exactly are string values stored? Are they stored in RAM? The reason why I ask, is the sprites I am designing will have several variations. For example, turning 180 degrees from left to right would be broken up into the left facing charactor, a 45 degree, a 90 degree (screen facing), a 135 degree, and lastly a 180 degree graphic. The way I am planning on using these characters is to have their value equal a string, then then during the transition do a CALL DELSPRITE(#), then CALL CHAR(char,nextsprite$), then CALL SPRITE(Next Sprite), etc. The same with characters that are moving horrizontally, have them transition from one graphic to the next until movement has stopped. I am doing it this way because with having 10-15 different sprites, all with variations, I'd prefer not to assign a character to each individual variation, would like to not run out, may need them. However, I'm not sure how much memory will be consumed. Is this a fairly standard practice in BASIC? In C++ when working with MCUs I would simply assign a value and the system would call the information when needed, but it wouldn't burn up all the working memory when it wasn't being used, as it is essentially just a pointer. But with the TI, I don't know a lot about how it likes to handle code.

Thanks, Opry. I've actually watched a few of your videos on youtube. Good stuff, man.

One more thing I thought about. If you do decide to start playing with AVR series MCUs, you really need to buy a USBasp. They're only a few bucks, and you shouldn't have any problem figuring out where to buy them from. You can write your code in any IDE that allows you to compile the machine code for that particular MCU, or use a separate compiler. The Arduino environment is one example, although not really C, but a C++ derivative. It's what I normally use. And I think in the latest release of the IDE the Teensy is supported, along with quite a few others. Of course there are Core Libraries available for MCUs not supported officially. The ATtiny series (Attiny85/45/25, Attiny84/44/24, Attiny2313, etc) is an example of that. But having the USBasp (or any other ICSP programmer) is crucial when you get away from the development boards. Although there is a library for using the Arduino has the programmer, I havent had great luck with it. And one more thing to consider hardware wise (I know I'm getting a little off subject here) is oscillators. Depending on what it is you're trying to do, you might want to look into crystals/ceramic resonators. Some projects need them, so do not. The AVR series isn't the most accurate frequency wise when it comes to the speed of the MCU. ATmega8/328 can be run at 8mhz just fine, but if your application is going to be communicating over I2C, UART, SPI, etc then you'll definately want to go with an oscillator of some kind. And this is dependent on application, i.e. 12mhz 16mhz, etc. Now considering I've gotten way off track, I'll try to refrain from future deviations of this thread. But would be happy to talk through PM if you have any questions. MCUs are where I cut my teeth...

I figured as much. However, as I stated above, I haven't delved into Assembly yet. Maybe eventually, but trying to relearn the basics right now. If the compiler can do a pretty good job it may be something I look into. I'd like to eventually learn Assembly, maybe even burn a cart or two if it turns out to be a halfway decent game. But, this is more of a learning project. And I'll probably decide to do the same if/when I sit down with the intent of learning assembly. There is a lot to learn before that happens, so it'll be something that is set on the back burner for now.

So it came preloaded with the code? If that's the case you better be able to read and write machine code. The avr series is a fun microcontroller to mess with. And you get a lot of band for your buck. There are variants in packages from DIP-8 to DIP-40, as well as SMD variants. Soon I want to play around with a neat little hack that a guy did a while back. See below.... http://m.instructables.com/id/Single-Chip-AVR-BASIC-Computer/ That should give you an idea of how powerful these MCUs are.

Vorticon, don't forget, if you're using the Teensy for it's USB support, there is also V-USB which adds USB support to most, if not practically all of the AVR series microcontrollers. I've used it with the tiny85 to construct virtual com ports, the mega8 to construct usb controllers for arcade systems, etc. Pretty handy tool to have. Especially since a Mega8 will cost you a buck or so along with a few resistors, diodes and caps, while the Teensy will cost you about $20.

Yeah, Mega Man was essential part of my younger (and really older) years of gaming. I don't care what system it's on, I'll play some MM. And honestly, that was a part of the inspiration for the concept I have. I won't go too far into the details. But the idea, and gameplay is somewhat similar, although, in many aspects I'm going for something completely different. So this method would probably fit well, and be a evolutionary throwback, if you will, to some of those games. 99er, I'll have to take a look into that. They may help a lot, especially if I end up going with Adam's approach.