Amiga.org
The "Not Quite Amiga but still computer related category" => Alternative Operating Systems => Topic started by: basman74 on May 27, 2010, 02:31:23 PM
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Hi All,
I would like to share with you all a story on the most frustrating, tedious but ultimately satisfying hobby project I have ever done!
Around a year ago, I had this crazy idea to build a replica of the classic systems that existed around the time of my youth but never had the chance to own. Back in the early days (mid-late 1980's), I was stuck with either a CoCo and then a PC-XT clone when nearly everyone around me had either a C64 or Amiga (or both! :)).
After putting aside the idea of recreating a commodore-related machine, as these were previously done by Dennis Van Weeren (Amiga 500 clone aka Minimig) and Jeri Ellsworth (C64 DTV), I originally decided on a PC-based platform due to having a soft spot for 'old beige' :D. As the project progressed, my focus then shifted to the machine that IMHO did much to help establish the IBM-PC as a viable platform for gaming - the Tandy 1000 clones.
To make things a little more challenging for me I did the following: I wanted the entire system hardware to be emulated by an 8-bit microcontroller!
Well, nearly twelve months (part-time) on, the prototype board works to the extent that it boots MS-DOS or FreeDOS, along with many various game titles supported by the system. The following Youtube videos show the prototype in action:
Latest video demo running Tandy 16-color games with 3-voice sound support:
http://www.youtube.com/watch?v=ZIW-iRq7Tnc
Second video demo running Tandy 16-color games:
http://www.youtube.com/watch?v=JDxYVR0bLQk
First video demo running ancient CGA style games:
http://www.youtube.com/watch?v=E-Kl4uciERM
Comments invited! Cheers and enjoy!
Regards,
Valentin Angelovski
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Awesome work! I applaud anyone who can see such a project through to completion like this! :) well done.
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Very very cool.
I have downloaded documentation on the Parallax Propeller chip in hopes of doing some homebrew pc stuff similar to this. I have a few chips ordered to experiment with and support stuff. Do you know about the Propeller and how it compares to the chip you used?
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@Valentin
Very nice, of course. I can't wait to see this come out! :afro:
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Hi!
Nice work. What Microcontroller did you use in the end? I didn't watch all of your videos but I did have a look at one of your demo vids where you showed some games running on the system. I'd be interested in more information about the hardware itself.
:)
AH.
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Ah, now I've found a video that details some information about the hardware.
AH.
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Great work! But it also makes me remember why I chose a C-64 and then an Amiga. The Amiga was light years ahead of Tandy and the MS-DOS world.
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All very well and impressive;I just settle for digging a Tandy 1000 out of my "collection",they are even on eBay still!
Tandy did a lot for the PC world by pushing the graphics ,sound, and expanded memory of their stock machines which were a step ahead of the genuine IBM.
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Dear all,
Thanks for all the positive responses! :)
To answer the specific questions:
@KThunder - While I am no expert on the Parallax propeller chip, one thing that I do know is that it has hardware support for mice/keyboards/video built-in (i.e. no need to attempt emulating these all in firmware like I did). So your task should be easier IMO. As I see it there are two ways to write an emulator using an embedded processor:
1.) Using available peripheral hardware support (i.e. far easier and quicker option)
2.) CPU Core alone bashes everything (i.e. the option I took, but do not recommend)
@redrumloa - Would be happy to release it as a product at some stage - once it passes 'alpha testing' that is! :D
@AppleHammer - While I cannot reveal the specific processor model at this time, since some of the hardware was originally designed for a commercial application for my current employer. What I can say however, the platform is essentially built around an MCU running around the triple-digit MHz ballpark, coupled to around 1MByte or so of SDRAM. I hope at some stage to put up a dedicated website for this project, complete with schematics along with more complete information..
@ferrellsl - Which makes it even more remarkable how a machine that started off with 'whopping' 4-color capability became the dominant gaming platform! :D
Regards,
Valentin
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@recidivist
You make a valid point, though I am certain your point could be equally applied to both the Minimig and C64-DTV as well. :)
Now while there may seem to be little point in getting a replica when you can buy (or already own) a real one, it should be noted there were some inherent features in the original architecture that I wanted to either update or improve upon in my own design:
1.) Possibility for easy switching between an original 8088 and later 80188/V20 CPU hardware behaviour for enhanced software compatibility i.e. POP CS only exists on the 8086 but not on later CPUs etc. To do this on a real Tandy 1000 you have to physically swap CPUs on the motherboard!
2.) Has a 'Tandy Graphics-to-VGA' video converter built-in! :)
3.) System RAM is configured as 704K conventional + 128K UMB RAM as standard
4.) BIOS ROM handlers are trapped and processed by the emulator natively, speeding up BIOS routines and potentially freeing up the Upper Memory Block for user RAM.
5.) System BIOS is copied to RAM on bootup and has mouse and HDD support built-in via INT's 13h and 33h respectively.
6.) Current maximum addressable 512MBytes of SD/MMC flash disk (Theoretical 8GB maximum)
7.) Small form factor(90mm x 110mm x 15mm overall) and very low power consumption (<0.5W)
8.) Could see these things easily retail for around USD$25-30 range - including a 512MByte flash disk. I wonder what it would cost to ship a replica (<50grams) instead of a real machine?
The downsides to this implementation (currently)?
1.) Lack of an standards-compliant expansion bus or game ports (only proprietary bus at the moment).
2.) BIOS ROM compatibility still incomplete (MUCH more to this than I first thought!).
3.) Only 32K of video RAM currently, so no multiple video pages in 320x200x16 color mode, though many games seem not to need it.
4.) Noise channel in the 3-voice sound circuit slightly different from original due to different implementation.
5.) Only 8088 CPU behaviour largely complete - currently working on NEC V20 emulation..
Regards,
Valentin
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Wow. Damn impressive. I never realized the 1000 was similar to the PCjr. I was never an Intel guy back then, though I knew how to use the PC computers. I do remember thinking "Thexder" was pretty cool, and I lament that I never obtained a copy of it for the 64 or Amiga.
Excellent work.
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I would like to share with you all a story on the most frustrating, tedious but ultimately satisfying hobby project I have ever done!
What great and truly inspiring work!
Do you have some technical details about your work somewhere?
For example, which mcu did you use, how exact is the emulation, etc?
I've been experimenting with something similar, maybe I should get my ass in gear and actually start working on the schematics.
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I never realized the 1000 was similar to the PCjr. I was never an Intel guy back then, though I knew how to use the PC computers.
To be honest neither did I, well at least not until I did some serious digging into the PCjr's colorful history in my search to find a machine to emulate. From memory, at the time I was fooling around with XT clones I had the impression our local Tandy store was still heavily pushing the CoCo3 (complete with running demos etc.) with a Tandy 1000 machine sitting farther back with an 'A>' prompt on it's screen.. Commodore resellers didn't make this mistake with their Amigas, that's all I will say!
I do remember thinking "Thexder" was pretty cool, and I lament that I never obtained a copy of it for the 64 or Amiga.
Actually I have similar feelings with respect to the Tandy 1000 version.. i.e. I prefer the 320x200 Tandy screen over the 640x200 EGA version (not to mention better sound!), Awesome game though, regardless of platform..
Wow. Damn impressive.
Thanks! :)
Regards,
Valentin
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Parallel port, parallel port, parallel port!!! ;)
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Where do I plug my Disney Sound System? :D
I love this, it's so cool!
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What great and truly inspiring work!
I am especially humbled by comments such as yours! Thankyou!
Of course, there were many people who helped inspire me as well (Dennis Van Weeren and Jeri Ellisworth playing their part as mentioned), But above all, I acknowledge Steve Wozniak's experiences with his projects in convincing me that if I'm really that keen then I should give this a go!
I've been experimenting with something similar, maybe I should get my ass in gear and actually start working on the schematics.
Best of luck in your endeavors - I urge you to 'know your hardware backwards' before getting started, and look forward to seeing some results! :)
Regards,
Valentin
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Do you have some technical details about your work somewhere?
For example, which mcu did you use, how exact is the emulation, etc?
I have detailed schematics system specifications etc. all fully documented (though not online, yet).
Cannot quite release details on the MCU at this time, for similar reasons to the documentation since they all make references to it. I can however comment on the emulation quality, but that'll have to wait until tommorrow (didn't realise it was 3am local time! :))
Regards,
Valentin
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Parallel port, parallel port, parallel port!!! ;)
Where do I plug my Disney Sound System? :D
Ah, you mean the printer port LPTn right? Please tell me you're only going to use it for it's originally intended purpose? :D
Okay, okay, hint taken! ;)
By far the quickest and easiest way for me to get an LPT (or perhaps other standard expansion possibilities, like game ports etc.) would be to implement it as a daughter-board. Would this suffice?
Regards,
Valentin
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What a silly thing to clone, but VERY VERY VERY cool regardless!!! WOW!
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What a silly thing to clone, but VERY VERY VERY cool regardless!!! WOW!
Thanks! All part of the fun really ;)
Well, looks like I'm doin another 3am-er :) To help satisfy interested member's curiosities about this project, I managed to scrape together a little web-corner that goes some way to explaining the project and where it might be headed. Will be expanding on the 'where it might be headed' bit a little more as soon I know where that is! :D
http://members.optuszoo.com.au/pioneer10/index.xhtml
The above is only a preliminary and very basic site until I can secure a more permanent home.. cheers and enjoy!
Regards,
Valentin
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Ah, you mean the printer port LPTn right? Please tell me you're only going to use it for it's originally intended purpose? :D
Okay, okay, hint taken! ;)
By far the quickest and easiest way for me to get an LPT (or perhaps other standard expansion possibilities, like game ports etc.) would be to implement it as a daughter-board. Would this suffice?
Regards,
Valentin
Intended purpose? Of course not :-) A daughter board would be fine as long as it is not bulky. The parallel port should be bog standard SPP. JMHO of course. I can see uses for Start Commander, 64HDD and others.
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Intended purpose? Of course not :-) A daughter board would be fine as long as it is not bulky. The parallel port should be bog standard SPP. JMHO of course. I can see uses for Start Commander, 64HDD and others.
@redrumola,
Actually, one of the other 'unintended uses' I have in mind for the printer port is to use it with one of those 3-axis CNC parallel port interfaces. Already have software that potentially could run quite happily on the board.. but cannot update the LPT data output because
'You've attempted to access I/O register 378hex which is currently just a silly byte variable in memory, please check your address value and try again!' :)
Regards,
Valentin
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Keep up the good work.
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Well, given it's been a month since my last post so I thought I'd add a little update :)
After some more prodding through my emulator firmware, I managed the following enhancements to the 'virtual PC core'
1.) I added the once-popular 320x200x256 VGA/MCGA 'chunky mode' (aka mode 13h) to the list of supported graphics modes into the emulated BIOS and display controller. The only real restriction here is color palette being 'fixed' at 256 colors (output DAC assignment is 3/3/2-bits R/G/B respectively) and even the order of those fixed positions cannot be altered (at this time). That said however, it works and as a result some VGA games now also run in addition to Tandy Graphics/CGA supported games. Screenshots:
Elite Plus -
Title Screen (http://members.optuszoo.com.au/pioneer10/elite1.JPG)
Player Screen (http://members.optuszoo.com.au/pioneer10/elite2.JPG)
SU-25 Sturmovik flight sim demo -
Player Screen (http://members.optuszoo.com.au/pioneer10/sturm2.JPG)
Gobman (PacMan clone by filipe mateus) -
Title Screen (http://members.optuszoo.com.au/pioneer10/gobman1.JPG)
Player Screen (http://members.optuszoo.com.au/pioneer10/gobman2.JPG)
'SLIQ' from the PC demoscene era -
Utah Teapot (http://members.optuszoo.com.au/pioneer10/sliq1.JPG)
To allow some of the games to run at an acceptable speed, I decided to push the virtual system to it's highest possible limit on this 8-bit MCU made the core run to an equivalent speed of 1075 v1.1 Dhrystones (i.e. going into 80286 country..). This was achieved using some inelegant display hacks and an overclocked core.. :( Using SRAM instead of SDRAM for system memory should fix this problem and also take the system to say, well beyond 3000 Dhrystones without overclocking.
QBASIC compiled programs now run quite happily on this thing, but the speed of some runtime files, particularily those needing FPU support isn't blistering (the 'SLIQ' demo for example runs but is terribly slow, mainly for this reason). I've had more successes speed-wise with the C/C++/Assembly demos.
2.) Parallel port daughtercard: The artwork for this is also ready, which will use a CPLD (view artwork (http://members.optuszoo.com.au/pioneer10/lptone.JPG)), though I cannot build it until I also do the artwork for an SRAM version of the mainboard (which will include an expansion header for the daughtercard).
Well, that's it from me for now.. I hope to put up another Youtube video demo on the VGA-related stuff shortly.
Cheers and enjoy!
Valentin
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@Valentin
Thanks for the update! About time to go into mass production soon? :hammer:
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Congratulations on your project. In the late '80s and early '90s I managed a Radio Shack franchise (Delmar Co., Middletown DE). The 1000s were an interesting series with a lot a varieties. The original was a desktop with a separate keyboard (basically a slightly improved PCjr clone), one later model was a console (rather amiga 1200 like) with MS-DOS in ROM.
I remember a later pizza box style 1000 as having the first 386SX processor that finally allowed the 1000s to run Windows.
BTW - I held on to some 1000 keyboards for the longest time because those keyboard had excellent feel and feedback (similar to IBMs excellent keyboards).
And of course most Tandy computers were made in the US at a Tandy owned plant that tested the motherboards for 24hrs in a elevated heat environment before assembly.
Our company also did a lot with the Color Computer. Motorola's basic design relied on the processor to perform a lot of duties that other machines (from Commodore and Atari) had dedicated chips for. But the processor in the Color Computer (a 6809) was more powerful than competing 8 bit machines. We actually had a three terminal point of sales system running on one Color Computer. The Color Computer 3 was a little too much of an upgrade, too late. It's a shame Tandy didn't take that machine more seriously. At the end of its lifecycle, running under OS9 Level II with third party disk controllers (both floppy and hard drive) and memory expansions up to 2 meg it was a fun machine to work with.
When Tandy EOL'd the Coco, we brought out a 68000 based OS-9 computer that we sold for a few years (we even ported a GUI to it).
That project, the System IV, led to the 68030 powered System V.
If the owner of the company hadn't passed on, we were planning on releasing an accesory card the used two components from the Coco3 (the 6809 CPU and the GIME graphic and memory controller chip). This would have given us backward compatibility with Color Computer software.
I keep track of Tandy related retro projects as well as Amiga related projects. Although there is one difference. While Amiga users may consider themselves hobbyists, they have updated machines that can run modern software. Tandy hobbyists are restricted by the limited power of their machines and a lack of upgrade paths. Plus they haven't got the kind of useful software you see in the Amiga market.
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Good work mate :)
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Great work!!!! and since your in Oz i can buy one when they are ready and it won't cost me my arms to ship it here! :D
Great work looking forward to a finished product.
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Great work!!!! and since your in Oz i can buy one when they are ready and it won't cost me my arms to ship it here! :D
Great work looking forward to a finished product.
Thanks mate.
You know, I never seriously considered this thing to be a 'product' per se, more of a 'hobby project' that I show to the missus every now and then who tells me 'that's nice, dear.. :)'
Perhaps it is time that I did. Would be interesting to see just how much this thing would cost per-board for a production run of say a couple hundred or so units..
Regards, Valentin
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Good work mate :)
Thanks mate :)
Cheers, Valentin
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@iggy
Thanks for your reply and also for sharing your interesting first-hand account with us!
As you've stated the CoCo3 was indeed a much more powerful beast than the machine it replaced (Z80-based CoCo2, of which I owned a clone) and put it inline with the Tandy 1000 and it's 8088 CPU, which in terms of basic performance was in the same league as the 6809..
One thing that I didn't get about the CoCo3: It wasn't compatible with either MS-DOS or most of the CoCo2 related stuff, yet it was a really nice machine? Tandy obviously wanted to try and the market to a higher level in 8-bit computing circles methinks..
Totally did not know about the enhanced 68k CoCo derivatives (the machines you referred to as systems IV/V) Good to see your old company (Delmar Co.) picked up the ball and make their own advanced CoCo derivatives after Tandy pulled out of that market! Really fascinating stuff! :)
Regards,
Valentin
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@Valentin
Thanks for the update! About time to go into mass production soon? :hammer:
Jim,
I've already begun the final assembly of some boards, though you'd probably laugh if you saw my initial assembly-line for the 'mass production' (gotta show a pic of that one!)
Hopefully once I have the emulation firmware finalised, there's not alot more that I would want to add to the SDRAM edition of the PCB. Please feel free to disagree, however.. :)
Cheers,
Valentin
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I've already begun the final assembly of some boards, though you'd probably laugh if you saw my initial assembly-line for the 'mass production' (gotta show a pic of that one!)
My in-house 'assembly-line (http://members.optuszoo.com.au/pioneer10/protos.JPG)'.. :D
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Progress update:
I have managed to add basic 256-palette DAC table support into VGA Mode 13h. Apart from correct colour representation, other cool things also now work, like colour cycling and video transitions/fading..
Of course, the table itself consists of 8-bit entries to match the video DAC on the board, so a conversion to/from 18-bit colour is performed before reading/writing to the table. While the conversion process is drastic to say the least, I think the result isn't as bad as one might imagine, though needless to say there's a noticeable difference.. :D I will leave it to others to comment on the visual improvement. Included are some screenshots of games after the inclusion of the palette DAC emulation:
Elite Plus -
Title Screen (http://members.optuszoo.com.au/pioneer10/new_elite1.JPG)
Player Screen (http://members.optuszoo.com.au/pioneer10/new_elite2.JPG)
SU-25 Sturmovik flight sim demo -
Player Screen (http://members.optuszoo.com.au/pioneer10/new_su25.JPG)
Gobman (PacMan clone by filipe mateus) -
Title Screen (http://members.optuszoo.com.au/pioneer10/new_gobman.JPG)
Displaying a JPEG image of the prototype board using 'LXPIC' DOS image viewer -
Displayed jpeg file (http://members.optuszoo.com.au/pioneer10/DXDemo_jpg.JPG)
Things to-do:
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1.) Test VGA output on as many LCD monitors as I can access, to ensure I got the timing right. Should work 100% on any old VGA CRT monitor however, as they are somewhat more forgiving.. :)
2.) Finish the Keyboard and hard-drive controller emulation portions of the firmware and finalize details on a simplified expansion bus..
Cheers and Enjoy!
Valentin
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Hi All,
After a few distractions, I finally managed to make a video of some early VGA games in action on the second prototype:
http://www.youtube.com/watch?v=diapn3Hkh1k
Note the specific color-cycling and video fade-in/out effects in most of the games demoed and also how slow Dune 2 runs on a (virtual) 10MHz 8088!
Cheers and enjoy!
Valentin
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Hi All,
Well, after around 18 months part-time worth of stuffing about I finally got round to completing my own version of a tiny PC clone (well, the first version anyway..)
Piccies of the 'FLEA88' system box..
Front view:
(http://members.optuszoo.com.au/pioneer10/flea88front.JPG)
Rear view:
(http://members.optuszoo.com.au/pioneer10/flea88rear.JPG)
Internal view:
(http://members.optuszoo.com.au/pioneer10/flea88internal.JPG)
Things added to the emulation firmware:
* Added virtual disney sound source, connected to the virtual LPT1 (look mom, no wires!) So now the PC speaker, Tandy Sound Gen. and Disney audio values are summed equally in firmware and sent out through the host audio DAC.
* Keyboard and mouse virtual interface improved considerably
* Int 10h video functions now largely complete, though some tiny quirks remain
* Hard disk write handler now complete so that high scores can now be saved (among other things), will need further testing
* Serial port COM1 now functional, albeit with basic support at the BIOS level only..
* CPU Trace Interrupt (01h) functionality added and fixed a stack (no pun intended) of CPU-related bugs..
Due to increasing time constraints, I've decided to keep the expansion possibilities to a minimum for the above showcase model.
Managed to get the firmware ready in time to showcase the system at our local (Amiga-oriented) computer user group over the previous weekend, where the response was quite positive overall.. No event pics unfortunately, as I had to leave far too early - oh well there's always next month.. ;)
Anyhow that's all from me for now - gotta get back to conqu... uh, I mean beta testing! :D
Cheers,
Valentin