Atom FDC from CP Microelectronics

[John_Newcombe]

Does anyone have any information on this board? Clearly its aa Atom FDC but seems to have sockets for memory etc. I am new to the Atom and am just getting my head around the peripherals etc. but couldn't find anything about this online.

As an aside, I thought it was interesting that the manufacturers mark included an apostrophie e.g. "CP Microcomputer's".



More photos...

[oss003]

Hi John,

nice find ... this is indeed a rare board.
I have never seen such a board.
Can you upload a picture of the backside of the PCB and if possible a ROM dump?
Would be interesting to see what the extra sockets do .... RAM/ROM?

PS there is some more text on the PCB

WJF....
M....
...er: with a sticker

Greetings
Kees

[roland]

I also haven't seen this board before. My best guess is that most of the sockets are for 16K RAM (#4000 - #7FFF). But a view of the back will probable tell us more like Kees said.

It can be a home made board, I couldn't find anything about CP Microcomputer's. The apostrophe might indicate that is was a non-English firm or person who designed the board.

[John_Newcombe]

Thanks all, the board is with a friend of mine at the moment, along with the Atom it came from. I'll be meeting him at the Synthesized event at the CfCH (1st July) and I'll bring it all back with me then. I'll then be able to update the posts with the photos etc. and get a dump of the ROM.

J

[BeebMaster]

Plastic 8271! Modern!

[John_Newcombe]

I have just added a photo of the reverse of the board to the initial post.

[Multiwizard]

How could I have missed this Topic?...

Nice board...

[Prime]

At a guess, I'd say the FDC section is probably a clone of the Acorn board, but with all the chips closer together to make more space
Assuming that then the ACORN DOS ROM is probably a standard Atom DOS.

As other people have said I would guess that the additional sockets are for filling up the $4000-$8000 area with RAM, and as they are 24 pin sockets, I guess they'd be designed for 6116, 2K*8 chips.

Cheers,

Phill.

[hoglet]

Assuming that then the ACORN DOS ROM is probably a standard Atom DOS.

It's interesting that the ROM has "Checksum 7C8DA" written on it...

The "standard" Acorn DOS rom that we have (e.g. in Atomulator) has:
- a CRC of #FCFE (using the ROM Signature program from Atomic Theory and Practice)
- a simple byte sum of #7622C

So it's possible that this ROM is different.

Are there different versions of the Atom DOS ROM that we know of?

Dave

[hoglet]

Does anyone know what the junk is at the end of the standard Acorn DOS ROM?

Code: Select all

00000f00  8d 07 02 a9 20 85 cd 85  ac a0 00 84 ee 84 c0 84  |.... ...........|
00000f10  b9 84 ba a2 04 20 13 e7  ca d0 fa 60 3f 28 33 44  |..... .....`?(3D|
00000f20  1e 02 19 1b 03 12 72 13  04 00 77 e4 13 e6 61 ea  |......r...w...a.|
00000f30  a0 ec f0 ea bc eb 53 e9  9e e8 49 43 45 53 2e 0d  |......S...ICES..|
00000f40  00 20 53 43 52 41 20 2a  20 24 30 34 30 30 0d 00  |. SCRA * $0400..|
00000f50  30 53 43 52 42 20 2a 20  24 30 35 30 30 0d 00 40  |0SCRB * $0500..@|
00000f60  53 43 52 43 20 2a 20 24  30 36 30 30 0d 00 50 53  |SCRC * $0600..PS|
00000f70  43 52 44 20 2a 20 24 30  37 30 30 0d 00 60 48 53  |CRD * $0700..`HS|
00000f80  59 4e 43 20 2a 20 24 33  33 0d 00 70 4b 42 49 4e  |YNC * $33..pKBIN|
00000f90  20 50 48 50 0d 00 80 20  43 4c 44 0d 00 90 20 53  | PHP... CLD... S|
00000fa0  54 58 20 24 30 30 45 34  0d 01 00 20 53 54 59 20  |TX $00E4... STY |
00000fb0  24 30 30 45 35 0d 01 10  46 49 4e 44 4b 59 20 42  |$00E5...FINDKY B|
00000fc0  49 54 20 24 42 30 30 32  0d 01 20 20 42 56 43 20  |IT $B002..  BVC |
00000fd0  52 45 50 54 54 54 0d 01  30 4e 4f 52 45 50 54 20  |REPTTT..0NOREPT |
00000fe0  4a 53 52 20 24 46 45 37  31 0d 01 40 20 42 43 43  |JSR $FE71..@ BCC|
00000ff0  20 46 49 4e 44 4b 59 0d  00 00 00 00 40 40 40 40  | FINDKY.....@@@@|

It looks like a fragment of Acorn System source code in an assembler format that uses * to assign a value to a symbol.

Dave

[hoglet]

Here's another interesting data point.

Henk Reinder's Atom Ware contains a commented disassembly of the DOS ROM.

The end of the ROM is different, and doesn't have that junk:
https://www.acornatom.nl/atom_handleidi ... ow2063.htm

It apprears to have a extra bootstrap code and a *OPT command.

The overview is also helpful:

This suggested the upgraded Acorn DOS came from TEAC.

Does anyone actually have this ROM?

[oss003]

Could it be an extension for the Diskrom because this rom has a *OPT command. Also a bootfile is described in the manual.

https://site.acornatom.nl/documentatie/ ... n/diskrom/

Greetings
Kees

[hoglet]

Could it be an extension for the Diskrom because this rom has a *OPT command.

The seems to be a different ROM entirely.

This Atom Nieuws article seems to describe the "upgraded" Atom DOS ROM:
https://site.acornatom.nl/documentatie/ ... 851096.gif

They refer to it as the TELEC version of the ROM, rather than the TEAC version.

I'm confused

Dave

[oss003]

The Diskrom is a #A000 rom.
The Telec diskdrive was a Teac .... can't read the manual because acoratom.nl is offline....
I never heard of a Teac DOS rom.

Greetings
Kees

[roland]

I have a Telec controller board and I’ll try if I can still read the ROM.
There was also DECADOS, which is an expanded version of the Acorn DOS for the Atom.

Btw … acornatom.nl is back online

[John_Newcombe]

I will do my best to get this ROM dumped next week.