Acorn System 1 TinyCAD and VeeCAD

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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anightin
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Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Wed Jan 09, 2019 10:33 pm

For those interested in capturing a System 1 in modern CAD tools I've just started a project to 'document' the System 1 '6502 Microcomputer'.

In the spirit of sharing, I'll update this post with my data-file attachments as I progress. I welcome anyone of a similar interest to check/improve/re-share as appropriate.

The tools I'm using are TinyCAD (2.90.00) and VeeCAD (2.38.0.0):
https://sourceforge.net/projects/tinycad/
https://veecad.com/

Firstly I'd like to dedicate this work to the fantastic pioneering steps of the original Acorn team, and to my friends and colleagues at Arm who are innovating the future as you read.

Thanks also to @Kazzie on this forum for inspiring me to have a go at building my own System 1 for 2 main reasons:

1) There is no better way IMHO to learn than by doing, and by celebrating each mistake as another step in the learning process
2) These computers are hard to come by, and just the thought of playing with an original System 1 and blowing it up would haunt me

Best wishes

anightin


This archive is my first few hours of experimenting with the tools to re-create a partial schematic and convince myself the development flow works. IT IS BY NO MEANS COMPLETE and may contain ERRORS on my part:

System1.TCLib : TinyCAD System 1 symbol library
System1_CPU_Card_v1.dsn : TinyCAD Schematic
System1_CPU_Card_v1.per : VeeCAD design containing strip-board layout
System1_CPU_Card_v1.zip
(20.86 KiB) Downloaded 9 times
Incremental update to refresh the component library and complete the list of CPU card ICs:
System1_CPU_Card_v2.zip
(29.28 KiB) Downloaded 2 times
Update of TinyCAD library and full CPU card schematic:
System1_CPU_Card_v3.zip
(60.78 KiB) Downloaded 3 times
Update of TinyCAD library and full CPU card schematic to rev 3 correcting NRDS and NWDS:
System1_CPU_Card_v4.zip
(64.8 KiB) Downloaded 3 times
Update of TinyCAD library and full CPU card schematic to fix some mis-routed signals and VCC:
System1_CPU_Card_v5.zip
(66.3 KiB) Downloaded 2 times
Update of all files to connect *CD lines on memories to IC10 output version, thanks to @bprosman for the hints:
System1_CPU_Card_v6.zip
(64.84 KiB) Downloaded 4 times
Last edited by anightin on Sat Jan 19, 2019 6:03 pm, edited 5 times in total.

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anightin
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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Sat Jan 12, 2019 11:11 pm

With the v3 files uploaded, the schematic should now be complete, and it creates a reasonable netlist which I need to double check:
TinyCAD v3 schematic.png
The netlist reads into VeeCAD and looks like it needs quite a bit of work to route -- as expected
VeeCAD v3 netlist.png
I may now consider a PCD CAD layout tool too -- any suggestions? I hear FreeCAD is good but no longer supported?

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by danielj » Sun Jan 13, 2019 8:00 am

Kicad is really the go-to open source cad/pcb package. Bit of a learning curve but it's very good. Even used (and developed) by Cern!

Ive used it for a fair few pcbs, and Simon Inns has done a lot with it including the latest beebscsi and the domesday duplicator.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by jonb » Sun Jan 13, 2019 9:54 am

+1 for KiCad, and Freerouter.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Sun Jan 13, 2019 11:54 am

Great thanks, will give that a try and report back :)

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Sun Jan 13, 2019 2:18 pm

Using Kicad regurarey myself, so if you need any help. What was the basic (original) schematic you worked from ?

Came from the SmArtwork, Orcad/Ultiboard, Layo, Protel99, Altium, Kicad route myself. Never got used to Eagle, for me the most non-intuitive program there is. Altium is still the holy grail but for a hobbyist hardly affordable.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by Kazzie » Sun Jan 13, 2019 5:40 pm

bprosman wrote:
Sun Jan 13, 2019 2:18 pm
Using Kicad regurarey myself, so if you need any help. What was the basic (original) schematic you worked from ?
This is important: there are two versions of the CPU board schematic online. The earlier one has the NRDS and NWDS lines the wrong way around, but the later one (issue 3, 1980) was fixed.

Best check this before you start laying things out on a PCB.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Sun Jan 13, 2019 7:28 pm

Thanks Kazzie, I wouldn't have spotted that had you not mentioned. Now updated my schematic to rev 4 with this fix.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Mon Jan 14, 2019 11:06 am

Does anyone have a link to the latest schematics ?

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by Kazzie » Mon Jan 14, 2019 2:37 pm

bprosman wrote:
Mon Jan 14, 2019 11:06 am
Does anyone have a link to the latest schematics ?
The Issue 1 schematic hosted at http://8bs.com/othrdnld/manuals/circuitdiagrams.shtml and http://speleotrove.com/acorn/acornSchematics.html have NRDS and NWDS the wrong way around.

4corn has the corrected Issue 3 diagram at https://www.4corn.co.uk/articles/diagrams/ , and http://www.vintageacorn.com/acorn_system1.html has both flavours: the "Circuit Diagram" is corrected, but the "Schematics" are the Issue 1 ones.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Tue Jan 15, 2019 2:25 pm

On the way.
System_One_Revival.JPG

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Tue Jan 15, 2019 2:26 pm

On a side note... is that INS8154 still sourceable ?

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by Kazzie » Tue Jan 15, 2019 3:33 pm

bprosman wrote:
Tue Jan 15, 2019 2:26 pm
On a side note... is that INS8154 still sourceable ?
Only through eBay sellers (to my knowledge). When I bought a pair, the only sellers were in China and the USA. Now it seems there are sellers in Australia, London and Hong Kong too, and there's a greater range of prices.
Last edited by Kazzie on Tue Jan 15, 2019 3:33 pm, edited 1 time in total.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Tue Jan 15, 2019 4:08 pm

Quick work on the schematic there!

I got mine from Australia near the end of Dec'18 :

https://www.ebay.co.uk/itm/INS8154N-128 ... ctupt=true

Postage was pretty quick, around about a week as I remember

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Fri Jan 18, 2019 9:04 pm

Getting there :
V0_5.JPG

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Fri Jan 18, 2019 10:27 pm

Nice Job, hopefully we are getting closer together: :D
2019-01-18 (1).png

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Sat Jan 19, 2019 10:48 am

Hope as well, this is my latest version :
Acorn_Sytem_1.pdf
(101.13 KiB) Downloaded 25 times

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by bprosman » Sat Feb 02, 2019 11:38 am

Dear all,

Today i uploaded my (sort of Final) Kicad files to :
https://github.com/bprosman/Acorn_System1_Revival

Feel free to use them as a starting point.
Myself I am going a different route, I still want to design an Acorn System X , 6502 Euro-card board. But I also want it to be reproducible. So a switch to a bit more modern components. I might use some of Phill Harveys as an inspiration.

If you spot any error's please let me know.

Kind regards, Bram

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by linker3000 » Sun Mar 03, 2019 12:08 pm

Just checking in to Say 'Hi'. There's the stirrings of a project to build a replica System-1 between a few of us on Twitter, so this is great to know about.

I also drew up the schematics in Kicad a couple of years ago but got distracted with other projects!

-- Nigel

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Tue Mar 05, 2019 12:18 pm

My journey so far -- all credit to a great community

1) Inspired to build a System 1 by kazzie's build
2) Captured CPU card schematic in TinyCAD and imported netlist into VeeCAD
3) Decided that actually I wanted to build a PCB
4) Recommended down the KiCAD route by danielj and jonb
5) Adopted bprosmans KiCAD scematics
6) Created a CPU card PCB layout using bprosmans netlist
7) A week later spotted trev-hams' reproduction PCBs and purchased a set
8) Started the build and ready to populate boards and test

Now investigating how to program some TESLA MH bipolar PROMs to hold the monitor
IMG_2845.jpeg

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by Kazzie » Tue Mar 05, 2019 1:08 pm

anightin wrote:
Tue Mar 05, 2019 12:18 pm
My journey so far -- all credit to a great community

1) Inspired to build a System 1 by kazzie's build
2) Captured CPU card schematic in TinyCAD and imported netlist into VeeCAD
3) Decided that actually I wanted to build a PCB
4) Recommended down the KiCAD route by danielj and jonb
5) Adopted bprosmans KiCAD scematics
6) Created a CPU card PCB layout using bprosmans netlist
7) A week later spotted trev-hams' reproduction PCBs and purchased a set
8) Started the build and ready to populate boards and test

Now investigating how to program some TESLA MH bipolar PROMs to hold the monitor
Looking nice, anightin! How are you doing with obtaining the ICs to populate the board?

If you haven't already, take a look at this conversation on another forum about programming the Tesla PROMs. And remember that you can put the monitor on an EPROM as a temporary (or permanent) solution.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Tue Mar 05, 2019 1:51 pm

I have all apart from some blank PROMs for the CPU board, and a MC14013BCP for the keyboard which is now on order thanks for asking, and for the reminder to the TESLA thread.

If I get the MC part first I may be able to borrow a set of System 1 PROMs for testing. I'll default to EPROM after that :)
IMG_2759.jpeg
Last edited by anightin on Tue Mar 05, 2019 1:56 pm, edited 1 time in total.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Wed Mar 06, 2019 1:52 pm

First signs of life, with borrowed System 1 PROMs pending burning some alternatives.

Also had to switch to alternate display -- thanks Trev-ham as the original I'd purchased only had 6 digits! Doh!

:D
IMG_2846.jpeg

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by Kazzie » Wed Mar 06, 2019 2:11 pm

Nice to see some lights there. I thought you had a full-length 9-digit display in your earlier picture of chips & bits, though. :?

I see the wire links for the PROM/EPROM decoding. Are the default memory & I/O decoding lines on the PCB, as with the later issue original boards?

If you decided you really wanted a bubble display, mine was salvaged from a faulty 1970s Rockwell calculator (8R). Similar models often sell for £5- £10 on eBay.

Edit: Come to think of it, that means my System 1's got a Rockwell 6502 and a Rockwell LED display! :)
Last edited by Kazzie on Wed Mar 06, 2019 2:12 pm, edited 1 time in total.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM (mid- restoration)
Acorn System 1 home-made replica

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Wed Mar 06, 2019 3:05 pm

Yes I have 2 bubble displays, I soldered up the header on the NS one I thought was 9 digits and it only happened to be 6 i.e. 9 plastic bubbles but the last 3 spaces unpopulated!

The spare in my bits got filed in my component trays in the shed -- which I'm now going to have to recover and re-solder a header.

Once that's recovered I'll try it and re-post.


The CPU board I have has the first two links cut so I've re-made them to enable monitor booting from the PROMs.

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by anightin » Wed Mar 06, 2019 8:53 pm

Relocated the TI spare and that seems to work nicely
IMG_2848.jpeg

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Re: Acorn System 1 TinyCAD and VeeCAD

Post by ask_nz » Thu Mar 21, 2019 8:22 am

=D> =D> =D>
Ade

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