Homebrew Tandy 1000 PC replica

[B00tDisk]

Where do I plug my Disney Sound System?

I love this, it's so cool!

[basman74]

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

[basman74]

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

[basman74]

Parallel port, parallel port, parallel port!!!

Where do I plug my Disney Sound System?

Ah, you mean the printer port LPTn right? Please tell me you're only going to use it for it's originally intended purpose?

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

[XDelusion]

What a silly thing to clone, but VERY VERY VERY cool regardless!!! WOW!

[basman74]

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!

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

[redrumloa]

Ah, you mean the printer port LPTn right? Please tell me you're only going to use it for it's originally intended purpose?

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.

[basman74]

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

[trekiej]

Keep up the good work.

[basman74]

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
 Player Screen

SU-25 Sturmovik flight sim demo -
 Player Screen

Gobman (PacMan clone by filipe mateus) -
 Title Screen
 Player Screen

'SLIQ' from the PC demoscene era -
 Utah Teapot

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), 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

[redrumloa]

@Valentin
 
Thanks for the update! About time to go into mass production soon? :hammer:

[Iggy]

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.

[MelbourneBen]

Good work mate

[Retro_71]

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!
Great work looking forward to a finished product.

[basman74]

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!
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

[basman74]

Good work mate

Thanks mate

Cheers, Valentin