Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
|
Forum Index : Microcontroller and PC projects : CMM2 - Go Go Go!!!!
Author | Message | ||||
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1985 |
https://www.bbcelite.com/ (not for me but you CMM2 guys seem to dig this sort of thing) Edited 2021-11-18 17:52 by CaptainBoing |
||||
thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3839 |
If only I had the time. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5716 |
As the routines are explained in detail, I can see that this might be of use to a lot of people. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
Calli Regular Member Joined: 20/10/2021 Location: GermanyPosts: 74 |
Time an lack of ASM experience... I always wondered (I played the C64 version days long) how they did that hidden line thingy on these computers. I did once a project where I could send 3d-lines to an oscilloscope and wished to do this... https://youtu.be/iETq18F3pug?t=104 Carsten |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5716 |
The old Vectrex game drove the X and Y plates and the cathode of the CRT directly IIRC. That allowed very fast control over the line with instant on and off at the beginning and end. It was a true vector display. Not all oscilloscopes give you that much access now, particularly to a blanking control input. The BBC did its line drawing using integer variables, which ran a lot faster than FP variables on that machine. They used a simple XOR command to plot to the screen and ignored the last dot of closed shapes so that it didn't get erased again. The routines appear to be in BASIC, not asm. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 3517 |
Old oscilloscopes (CRT type) needed beam blanking to get from A to B invisible (in fact "without leaving a trace"). CRT based TV's have the same (Horizontal blanking and vertical blanking). Hence these signals names on the VGA connector (original CRT based). Modern (LCD) type displays can go from A to B directly (addressable pixel based). That is why there generally is no Z-input (blanking input) on modern scopes. Edited 2021-11-19 22:45 by Volhout PicomiteVGA PETSCII ROBOTS |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5716 |
I miss spot wheel patterns for frequency measurement. lol Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
Calli Regular Member Joined: 20/10/2021 Location: GermanyPosts: 74 |
To be clear, these videos are directly from my project but it uses a method from Trammell Hudson, which draws visible lines slow and the movements very fast and works on every scope! I did games and some Demos where I feed 3D-Graphic from the Blender viewport to it. https://trmm.net/V.st/ for the code, it uses a Teensy >3.x and DA-Chips. EDIT: better link: https://www.heise.de/make/artikel/Retro-Spiele-auf-dem-Oszilloskop-3908332.html https://www.heise.de/select/make/2017/6/1513978999984951 I need to look closer to the code of Elite, it uses Basic?!!?!?!?! wow. Carsten Edited 2021-11-21 00:11 by Calli |
||||
karjo238 Regular Member Joined: 12/10/2018 Location: New ZealandPosts: 54 |
If I return to university next year, I'll have a little bit of spare time, and this is the kind of thing I'd love to get my teeth into. Thanks for the link in any case. That website is absolutely fascinating |
||||
SimpleSafeName Senior Member Joined: 28/07/2019 Location: United StatesPosts: 286 |
If there is any I haven't come across it. All ASM so far. |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5716 |
Yep. All ASM. :( My mistake, sorry. This section had me confused as it shows how things were done, but line drawing (which is what I was interested in at the time) is shown written in BASIC. https://www.bbcelite.com/deep_dives/ Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1985 |
Some of the code that I saw was contained in Beeb Basic inline assembler ASM[...] statements, so yeah, not really basic but using it as a container. 35 years ago, my then employer used Amstrad CPC6128s (suitably gutted) as controllers for RADAR consoles they manufactured - it was an inexpensive, well-thought out & engineered Z80 platform with upto a MB of RAM, the same on sideways ROMs with FAR CALLing and easy IO expansion and the PSU in the monitor would go down to 90VAC - way better than an IBM PC which meant it was great for deployment in third world contries where the power was flaky. One of my tried an tested methods on them was to write and debug systems in BASIC and then hand-compile, into assembler, assemble with Cromemco's ASM ported to CP/M. The output HEX file was then loaded to memory with a home-grown basic loader and saved out as a binary. It was a joy due largely to the very well written and documented firmware. I used to love that. It was a nice environment and hand-compiling a basic listing was a lot of fun and paid instant benefits. Although the toolchain looks a nightmare compared to modern methods (well, not too much) it was a breeze and wasn't cumbersome. Edited 2021-11-24 03:25 by CaptainBoing |
||||
SimpleSafeName Senior Member Joined: 28/07/2019 Location: United StatesPosts: 286 |
No worries, the ASM was more interesting anyway. :) I spent some time on your site tonight, interesting history! I have some Z-80 stuff including a couple of Fox MT-Z80 trainers (a later version to mine can be found here: https://www.youtube.com/watch?v=WiPoMvBL9u4). Plus a decent collection of Z80 chips. |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5716 |
Of course, should you do an almost direct copy of the 6502 ASM into MMBasic on the CMM2 you might only need to slow it down a bit to get Elite playable... :) There are still bits of the Nascom/Gemini story that I don't think have been told. Probably for legal reasons as some of the people involved may still be around. I would also love to know what happened to the elusive Richard Beal, the writer of the Nascom monitors (and some of the ROMs on the Gemini cards). His Z80 programming was amazing and those EPROMs are a work of programming art. Well worth investigation if you are a fan of Z80 code. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
Print this page |