Building an Acorn System 1

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
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anightin
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Re: Building an Acorn System 1

Post by anightin » Wed Jan 09, 2019 9:13 am

Whilst waiting for the components I thought I'd start laying out the design which is made much easier by Chris T's easy to read diagram and parts list.

I had a go first with TinyCAD with a plan to layout in VeeCAD using a netlist import. I also thought it would be easier to create my own System1 parts library so experimented with the main ICs first:
2019-01-09.png
I liked VeeCAD free version so I ended up purchasing the full version as it has a router:
2019-01-09 (1).png
Hopefully over the next couple of weeks I can get the CAD files sorted. Happy to share the files if anyone wants to check my work. Where is the best place to put them on this site?

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1024MAK
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Re: Building an Acorn System 1

Post by 1024MAK » Wed Jan 09, 2019 9:30 am

anightin wrote:
Wed Jan 09, 2019 9:13 am
Hopefully over the next couple of weeks I can get the CAD files sorted. Happy to share the files if anyone wants to check my work. Where is the best place to put them on this site?
If they are not too large, zip them up and add as an attachment to a post in this thread, or if you prefer, start a new thread in this section of the forum (Acorn Atom and System), then you can edit and add to the first post of the new thread, so that they are all in one place.

Alternatively, you could use one of the file sharing sites, then link to it in your post(s).

Mark

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anightin
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Re: Building an Acorn System 1

Post by anightin » Wed Jan 09, 2019 10:37 pm

Good suggestions Mark, have created a new thread and posted my current work here: viewtopic.php?f=44&t=16322#p224778

Kind Regards

anightin
Last edited by anightin on Wed Jan 09, 2019 10:37 pm, edited 1 time in total.

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Re: Building an Acorn System 1

Post by daveejhitchins » Thu Jan 10, 2019 6:20 pm

I've just decoded the Intel HEX file into Binary and then split the High and Low nibbles into two seperate files for programming the PROMS.

Here are the code blocks:

Intel HEX:

Code: Select all

:18FE0000A006B500206FFECA888810F6861AA2078E220EA000B5108D29
:18FE1800210E8E200EAD200E293F240F1018C938B0068619A940850F76
:18FE3000A10088D0FBCA10DBA50E30D21014E419D0EEC9389004A980BF
:18FE4800D0E4C50FF0E2850F4938291FC910850DA61A8C210E60A10004
:18FE6000A006D00BA003B500206FFE8888B501C848207AFE88684A4A32
:18FE78004A4A841A290FA8B9EAFFA41A991000602064FE200CFEB0207B
:18FE9000A0040A0A0A0A0A3600360188D0F8F0E8F606D002F607B50669
:18FEA800D508D004B507D50960A0408C220EA0078C200E6A6A20CDFEDB
:18FEC0006A8D200E8810F620CDFE8C200E20D0FE841AA04888D0FD8881
:18FED800D0FDA41A60A0082C200E30FB20D0FE20CDFE0E200E6A88D023
:18FEF000F6F0DAA2FF9A8E230E860EA080A209940ECAD0FB200CFE90F0
:18FF0800F22907C9049025F06FC906F009B00FA50AA60BA40C40F60011
:18FF2000D00CF601B008B500D002D601D6002064FE4C45FF84168417C3
:18FF38000AAA49F785102088FEE002B015205EFE200CFEB0BCA1000A1E
:18FF50000A0A0A050D81004C45FFD0036C0200E004F036A208861020AD
:18FF680088FEA204B50520B1FECAD0F8A10620B1FE20A0FED0F6F02A26
:18FF8000A20420DDFE9505CAD0F820DDFE81068D210E20A0FED0F3F0ED
:18FF980011A100F0068518A900F002A5188100205EFE4C04FF6C1C00E0
:18FFB0006C1E00850A860B840C6848850DA20DA9FF850E2000FEBA8675
:18FFC80013C88412D8BD020138E51B9D02018511BD0301E9009D03015F
:18FFE0008510A2132000FE4C07FF3F065B4F666D7D077F6F777C585E72
:08FFF8007971ADFFF3FEB0FFCB
:00000001FF
Binary:

Code: Select all

A0 06 B5 00 20 6F FE CA 88 88 10 F6 86 1A A2 07
8E 22 0E A0 00 B5 10 8D 21 0E 8E 20 0E AD 20 0E
29 3F 24 0F 10 18 C9 38 B0 06 86 19 A9 40 85 0F
A1 00 88 D0 FB CA 10 DB A5 0E 30 D2 10 14 E4 19
D0 EE C9 38 90 04 A9 80 D0 E4 C5 0F F0 E2 85 0F
49 38 29 1F C9 10 85 0D A6 1A 8C 21 0E 60 A1 00
A0 06 D0 0B A0 03 B5 00 20 6F FE 88 88 B5 01 C8
48 20 7A FE 88 68 4A 4A 4A 4A 84 1A 29 0F A8 B9
EA FF A4 1A 99 10 00 60 20 64 FE 20 0C FE B0 20
A0 04 0A 0A 0A 0A 0A 36 00 36 01 88 D0 F8 F0 E8
F6 06 D0 02 F6 07 B5 06 D5 08 D0 04 B5 07 D5 09
60 A0 40 8C 22 0E A0 07 8C 20 0E 6A 6A 20 CD FE
6A 8D 20 0E 88 10 F6 20 CD FE 8C 20 0E 20 D0 FE
84 1A A0 48 88 D0 FD 88 D0 FD A4 1A 60 A0 08 2C
20 0E 30 FB 20 D0 FE 20 CD FE 0E 20 0E 6A 88 D0
F6 F0 DA A2 FF 9A 8E 23 0E 86 0E A0 80 A2 09 94
0E CA D0 FB 20 0C FE 90 F2 29 07 C9 04 90 25 F0
6F C9 06 F0 09 B0 0F A5 0A A6 0B A4 0C 40 F6 00
D0 0C F6 01 B0 08 B5 00 D0 02 D6 01 D6 00 20 64
FE 4C 45 FF 84 16 84 17 0A AA 49 F7 85 10 20 88
FE E0 02 B0 15 20 5E FE 20 0C FE B0 BC A1 00 0A
0A 0A 0A 05 0D 81 00 4C 45 FF D0 03 6C 02 00 E0
04 F0 36 A2 08 86 10 20 88 FE A2 04 B5 05 20 B1
FE CA D0 F8 A1 06 20 B1 FE 20 A0 FE D0 F6 F0 2A
A2 04 20 DD FE 95 05 CA D0 F8 20 DD FE 81 06 8D
21 0E 20 A0 FE D0 F3 F0 11 A1 00 F0 06 85 18 A9
00 F0 02 A5 18 81 00 20 5E FE 4C 04 FF 6C 1C 00
6C 1E 00 85 0A 86 0B 84 0C 68 48 85 0D A2 0D A9
FF 85 0E 20 00 FE BA 86 13 C8 84 12 D8 BD 02 01
38 E5 1B 9D 02 01 85 11 BD 03 01 E9 00 9D 03 01
85 10 A2 13 20 00 FE 4C 07 FF 3F 06 5B 4F 66 6D
7D 07 7F 6F 77 7C 58 5E 79 71 AD FF F3 FE B0 FF
High nibble:

Code: Select all

A0 B0 26 FC 88 1F 81 A0 82 0A 0B 18 20 82 0A 20
23 20 11 C3 B0 81 A4 80 A0 8D FC 1D A0 3D 11 E1
DE C3 90 A8 DE C0 FE 80 43 21 C1 80 A1 82 06 A0
A0 D0 A0 B0 26 F8 8B 0C 42 7F 86 44 44 81 20 AB
EF A1 91 06 26 F2 0F B2 A0 00 00 03 03 08 DF FE
F0 D0 F0 B0 D0 D0 B0 D0 6A 48 20 A0 82 06 62 CF
68 20 81 F2 CF 82 02 DF 81 A4 8D F8 DF A1 6A 02
20 3F 2D F2 CF 02 06 8D FF DA F9 82 08 0A 8A 09
0C DF 20 F9 F2 0C 09 2F 6C 0F 0B 0A 0A 0A 04 F0
D0 F0 B0 B0 D0 D0 D0 26 F4 4F 81 81 0A 4F 81 28
FE 0B 12 5F 20 FB BA 00 00 00 08 04 4F D0 60 0E
0F 3A 08 12 8F A0 B0 2B FC DF A0 2B F2 AF DF F2
A0 2D F9 0C DF 2D F8 08 20 2A FD FF 1A 0F 08 1A
0F 0A 18 02 5F 40 F6 10 61 08 08 08 06 48 0A 0A
F8 02 0F B8 1C 81 DB 00 3E 19 00 81 B0 0E 09 00
81 A1 20 F4 0F 30 54 66 70 76 77 55 77 AF FF BF
Low nibble:

Code: Select all

06 50 0F EA 88 06 6A 27 E2 E0 05 0D 1E E0 ED 0E
9F 4F 08 98 06 69 90 5F 10 80 BA 0B 5E 02 04 49
0E 98 04 90 04 5F 02 5F 98 9F 90 5D 6A C1 E0 10
06 0B 03 50 0F E8 85 18 80 AE 88 AA AA 4A 9F 89
AF 4A 90 00 04 E0 CE 00 04 AA AA A6 06 18 08 08
66 02 67 56 58 04 57 59 00 0C 2E 07 C0 EA A0 DE
AD 0E 80 60 DE C0 E0 0E 4A 08 80 D8 0D 4A 00 8C
0E 0B 00 E0 DE E0 EA 80 60 A2 FA E3 E6 E0 02 94
EA 0B 0C E0 29 79 40 50 F9 60 90 F5 A6 B4 C0 60
0C 61 08 50 02 61 60 04 EC 5F 46 47 AA 97 50 08
E0 20 50 EE 0C E0 C1 0A AA A5 D1 0C 5F 03 C2 00
40 62 86 00 8E 24 55 01 EA 08 16 01 E0 0E 06 0A
24 0D E5 5A 08 0D E1 6D 1E 00 E0 30 11 00 65 89
00 25 81 00 EE C4 FC C0 CE 05 A6 B4 C8 85 D2 D9
F5 E0 0E A6 38 42 8D 21 85 BD 21 51 D3 19 0D 31
50 23 00 EC 7F F6 BF 6D D7 FF 7C 8E 91 DF 3E 0F
If someone could check for me, please?

System 1 Code.zip
(3.67 KiB) Downloaded 28 times
Dave H :D
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linker3000
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Re: Building an Acorn System 1

Post by linker3000 » Sun Mar 03, 2019 5:11 pm

Just checking in with my System 1!

https://imgur.com/gallery/f7zZR

There's a few peeps on Twitter thinking about building a replica, including last cutting the keyboard panel and sourcing some right-sized keycaps, so it would be good to sync up.

I started thinking about making a replica a couple of years ago (http://forum.6502.org/viewtopic.php?t=3286) and drew up the main board schematic in Kicad, but other projects took my attention - I have all the components needed but have to find some time - it always boils down to that.

Anyway, keep up the good work! I'll help out where needed/able.

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Re: Building an Acorn System 1

Post by Kazzie » Mon Mar 04, 2019 1:58 pm

Nice to see you, linker3000, your thread on 6502.org is one of the many I'd read before I started building my own System 1!

I've recently finished soldering up the cassette interface on the vacant space of my eurocard, and a test with an oscilloscope showed it was generating a sequence of different frequencies when asked to "record" the contents of the Monitor EPROM (after cleaning up one stray track of solder).

Here's a quick picture from last week, while I was still waiting for the op-amp to fill the socket in the upper right corner:
IMG_20190226_1422505.jpg
The electrolytic capacitor's a substitute from my bitbox, 10uF vs 15uF iirc. We'll see if that mucks things up at all.

The Op-Amp's now in place, and the next step will be to fetch my wife's cassette recorder (and box of tapes) from the attic. I know I could record and playback via my laptop, but somehow that wouldn't feel right.

If it does pass that test, I will use my laptop to play it a MIDI-savefile from the emulator on Speelotrove's site, to check that it's not just reading and writing in its own strange dialect. :wink:
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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anightin
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Re: Building an Acorn System 1

Post by anightin » Mon Mar 04, 2019 4:22 pm

Good to see, I am still trying to source a pair of blank DM 74S571s to hold the monitor code. Will have to resort to an EPROM or Tesla MH parts if I dont come up with anything soon.

Every one I've sourced from Ebay so far has either been full of 0xFs or random data of some kind despite sellers saying that they are blank checked.

Will post some pictures of the build soon.

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Re: Building an Acorn System 1

Post by IanS » Mon Mar 04, 2019 4:50 pm

anightin wrote:
Mon Mar 04, 2019 4:22 pm
Every one I've sourced from Ebay so far has either been full of 0xFs or random data of some kind despite sellers saying that they are blank checked.
Full of 0xF's is usual the default empty state in (E)PROM's, I assume the 4 bit PROM's in the System 1 are the same. You can usually only knock bits down to a zero.

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Re: Building an Acorn System 1

Post by Kazzie » Mon Mar 04, 2019 5:19 pm

IanS wrote:
Mon Mar 04, 2019 4:50 pm
anightin wrote:
Mon Mar 04, 2019 4:22 pm
Every one I've sourced from Ebay so far has either been full of 0xFs or random data of some kind despite sellers saying that they are blank checked.
Full of 0xF's is usual the default empty state in (E)PROM's, I assume the 4 bit PROM's in the System 1 are the same. You can usually only knock bits down to a zero.
Fusible PROMs are all zeros when fresh from the factory, blowing a fuse changes a "bit" to a one.

EPROMS, on the other hand, are all ones (0xFF) when erased, and require the zeros to be "programmed in".
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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Re: Building an Acorn System 1

Post by linker3000 » Mon Mar 04, 2019 7:07 pm

Kazzie wrote:
Mon Mar 04, 2019 1:58 pm

If it does pass that test, I will use my laptop to play it a MIDI-savefile from the emulator on Speelotrove's site, to check that it's not just reading and writing in its own strange dialect. :wink:
I couldn't get my System 1 to load anything from the MIDI player - the display would react, but no valid data ended up in RAM. After trying for a while, I had an email conversation with Mike Cowlishaw (from Speleotrove):

"I have a feeling that the emulator-generated tones could be recognised by the emulator but not the real hardware ... but I really don't remember. They may just need low-pass filtering or something..."

So be aware that the MIDI player might not be a reliable test.

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Re: Building an Acorn System 1

Post by Kazzie » Mon Mar 04, 2019 9:06 pm

linker3000 wrote:
Mon Mar 04, 2019 7:07 pm
Kazzie wrote:
Mon Mar 04, 2019 1:58 pm

If it does pass that test, I will use my laptop to play it a MIDI-savefile from the emulator on Speelotrove's site, to check that it's not just reading and writing in its own strange dialect. :wink:
I couldn't get my System 1 to load anything from the MIDI player - the display would react, but no valid data ended up in RAM. After trying for a while, I had an email conversation with Mike Cowlishaw (from Speleotrove):

"I have a feeling that the emulator-generated tones could be recognised by the emulator but not the real hardware ... but I really don't remember. They may just need low-pass filtering or something..."

So be aware that the MIDI player might not be a reliable test.
Useful to know, thanks. :)
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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Re: Building an Acorn System 1

Post by anightin » Fri Apr 05, 2019 3:33 pm

Changing subject slightly.... So haven't had any joy in finding blank Nat Semi DM74S571 PROMs, the ones from Ebay are generally used despite some saying new. All sellers have readily refunded however, so at least I have been able to continue my search.

The Tesla MH74S571 ones tend to be blank but I haven't found anyone with a programmer that can handle them yet.

The following programmer claims to support them if anyone is lucky enough to own one:
https://www.dataman.com/featured/datama ... ammer.html


A colleague of mine kindly dug out his parallel port MMLV48 programmer and dusted off his Win95 PC for me which supports the equivalents below:

AMD 27S13
Philips Signetics 82S131

Checked out the AMD PROMs first, all good, then the Signetics, also good so great result!
IMG_3210.jpeg
Hope this helps anyone wishing to use the PROM approach to their System1 build.

I realise that EPROM is always an option but want to keep that free for expansion. In any case the PROMs might become spare as a future upgrade to a System 2 is on the list for some time this year (the WIP board in the background).
Last edited by anightin on Fri Apr 05, 2019 8:43 pm, edited 3 times in total.

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