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Ursus

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About Ursus

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    Austria
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    8 bit Computer

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  1. I found two threads in the forum that go well with the processors. I just overlooked them before I started. @mizapf: I think you talked about this thread. (#7) In this thread @stuart has linked a slightly older thread (#20). A very interesting text.
  2. Thanks to everyone, I learned a lot today. Now some things are becoming a bit clearer for me. 😊
  3. Do I understand correctly that the 8K ROM on the cartridge (if available) is addressed via the memory map > 6000 to > 7FFF, the GROM on a cartridge, however, via > 9800 & > 9802 and GROM 3-7> 6000 to > F7FF (GROM 0-2> 0000 to >57FF (is onboard)).
  4. In which language were the XB, SXB, RXB, ... written?
  5. At that time there was also AMI as a 9000 producer: https://www.cpu-world.com/CPUs/TMS9900/AMI-S9900P.html Please forgive me, unfortunately I am still at a very low level of understanding, but I would like to understand it 😅. Is it a question of where a basic interpreter written in assembler could be? Just for me to understand: The console ROM is located > 0000-1FFF and is only 8K in size. The GPL interpreter is > 0024-08FF and the basic interpreter is > 18C8-1C9A. (Basic with the C64 requires 8K ROM + part of the KERNAL ROM which I know, but was only very limited.) So there is no other "internal" space in the console for the ROM. Therefore you could only connect it externally. Am I right? Then only three memory locations remain: DSR, Cartridge and Memory Expansion. > 6000 to> 7FFF for the cartridge, a maximum of 8K ROM is available or "banking". Did I get it right? Wouldn't it be possible in part of the memory expansion?
  6. @mizapf thanks 😊 This means that the TMS9985 would have solved the problem with the 14-bit address bus, since it has the same number of address lines as the TMS9990, but the TMS9985 would have had fewer interrupts than the TMS9990. I only have a single drawing with the TMS9985 and then there also seem to be less INT when I see it correctly. I understand correctly that the 9980A could have used 11 CRU-bits with the addresses 0000-0FFE and could only address the internal components (keyboard, cassettes, ...). The external peripheral devices (PEB, Hexbus, ...) not? Would the 9985 have been able to do this or was no periphery planned at all at the time of dimension 1 & 4? 😅 The 9995 seems to be the best 16/8 bit variant of the series in all points, fulfills the points of the 9900 and more. I'm just new and possible that I got it wrong. I perceived that the TI Basic interpreter was written with GPL and the GPL interpreter with assembler.
  7. Hello 😊, it's not an essential question, but I'm trying to understand the history of the TI-99 and the relationship between the individual processors better. In the years 1976 to 1981 various processors of the 9900 family came out. I have tried to compare some data here. If I have made mistakes, please tell me. 😅 TMS 9900: TI-990/4 minicomputer, TI-99/4 (A) and SGCPU TMS 9980A / TMS 9981: TM-990/189 SBC TMS 9940 (1979):? TMS 9985 (never released): originally planned for Dimension 1&4 TMS 9995: Tomy Tutor, TI-99/2 & TI-99/8, Geneve TMS 9500: TI-99/4B, TI-99/5 TMS 99105: SGCPU (only planned) TMS 99110:? TMS 99120 (never released) TMS 9985: The following drawing can be found on page 52 of the TI-99_4 New Technician Guide (Reduced pp 001-080).pdf: This drawing clearly shows that the TMS9900 was not the planned processor. Thanks Toucan & CB Wilson that I can see the original drawing. https://atariage.com/forums/applications/core/interface/file/attachment.php?id=695856 If I have understood correctly, the 9980 series is the “stripped down” 9900 series - 16 bit processor with 8 bit data (9980) instead of 16 bit data (9900) (similar to Intel 8086 and 8088 ???) 🤔? The 9940 is a variant with internal RAM / ROM. The 9985 should become a (2x?) faster 9980A based on the 9940 with internal RAM / ROM? 🤪 Am I correct with the assumption that the internal 256 bytes were the CPU RAM that was mounted on the mainboard of the TMS 9900 external? Why wasn't the TMS 9980A used instead of the TMS 9985 with an external RAM & ROM, like the TMS 9900? This already existed. The topic has already been addressed "briefly" in the following thread #99: Is there any new information? TMS 9995: I read somewhere that the GPL should integrated in the hardware of the 9985. It was not successful, which is why the TI Basic had to be interpreted twice with the 9900. The TMS 9995 came out in 1982 with the Tomy Tutor and was also intended for the TI-99/2 and TI-99/8. Fabrice has one of the two working TI-99/5 and it had a TMS 9500 (9995 without internal RAM). There was probably only a handful of the TMS 9500 (I think it was built into the TI-99/4B). Was it possible with the TMS 9995 to solve the problems with the GPL? Thank you and best regards Michael 😊
  8. Hello, a good chance to introduce myself, because it will be my first post in this forum. The computer cost a lot of money back then. I got my TI99/4A at Christmas 1982 (age 11). The father of a friend of mine had a TI99 at the time, and he himself had a ZX81. And so we met alternately to work with the computer. I spoke to my mother on the phone today and she told me that they wanted to learn how to use the computer with me back then. But they soon gave up. Christmas 1983 I got the Extended Basic, it was the only gift they could afford for the occasion. At the time, my mother did not understand why the little thing was more important to me than many small gifts. I can still remember, it was the only thing I wished for. To store the programs, I had a tape recorder, not from Texas Instruments, and it had NO counter. That was very exciting because when we were looking for a game, I had to find the spot by feeling. Most of the time I loaded a game that I didn't want at all. 😉 I had only a few command modules, Extended Basic, Parsec, Music Maker and Mini Memory. With the exception of Extended Basic, we all bought second-hand at the time. I became TI joysticks and the speech synthesizer, which I was particularly proud of. We typed most of the games from various magazines. In my school class at that time there were three computer groups (VIC20, ZX 81/Spektrum and two 😉 with a TI99). We were friends with each other, but also opponents. On our way to school in Vienna (Austria) we had an office supplies store, I think it was from Olivetti. But I'm not sure anymore. In the shop the many cartridge boxes were on a shelf and every day we saw whether something new was added. One day I saw how they redesigned the storefront and the Texas Instruments items disappeared and weren't supposed to be returning. That was the end. The C64-II followed with a lot of games, but I never found the connection to this one. Before I went to high school, we sold my C-64 without a lot of emotion, my TI99 came in the box, where it was to spend the next few years. In 2001 I moved to Salzburg (10 km from “Sound of Music”) and I knew that I would not take my TI with me and that I would leave it in Vienna. I wanted it to be in good hands and gave it to my friend's father with all my belongings, who had brought me to the TI99/4A at the time. I hadn't played or worked with him for a long time, had previously used XBasic to program with it, I didn't fulfill my wish to learn assembler any more. I found it difficult to give away my original box with all the parts. I thought to myself I would leave my childhood behind and start a family now and I don't need a “home computer” anymore. I took a PC with me, it was an i486. After that came another PC and I think 3 or 4 laptops. This friend's father died two years ago and I was told that the father had given the two TI99s away a long time ago. Last year I started working with the Micro: bit... it brought me back to the "home computers" in my mind. I wanted to have the feeling of having direct contact with the hardware again. Only then did I realize that the scene with the 8-bit computers (😉) still exists. In 1983 I didn't really know what the difference between 8- and 16-bit was, I just knew the TMS9900 was "more". I looked at the C64 scene, the project with “Commander X16”, the project of Ben Eater and finally I came across the videos from Adrian's Digital Basement and Noel's Retro Lab back to the TI99 and then my heartbeat got faster again. I'm looking forward to working with the TI99 again and this time with assembler 😊. Now I want to get to know the device better than I knew it back then. Guys you do a great job, thank you for collecting things and keeping them so well and thinking ahead. It's so fun to rediscover things. Mike
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