Elektor SCMS stripper ROM

[james_s]

A friend of mine is looking for an image of the ROM used in this old project that was published in Elektor about 20 years ago http://www.minidisc.org/copybit/copybit.html

I did some searching but came up dry, somebody out there must have built one of these back in the day though. It's just a 27C512 so it's trivial to dump it if an original is found.

[amyk]

It's a state machine with only 128 states. Judging by what it does it would probably not be hard to figure out a possible configuration of the contents.

[james_s]

Well that's not off the table, but the ROM has got to be out there somewhere and finding it would save him from reinventing the wheel. There are other similar projects out there too but I think he's already got a PCB for this one laying around.

[ozcar]

From the 7-8/1998 English language edition: "The data for the EPROM is provided by a small Pascal program that produces a binary file of 32768 bytes." Maybe that program is out there somewhere?

They did continue with "Constructors need not concern themselves with this since the programmed EPROM is readily available through our Readers’ Services.". So, there you go then, as a certain state politician in this country used to say, "donchoo worry about that".

[james_s]

Yeah he hasn't been able to find that program either, and sure if it were 20 years ago I'm sure he'd just buy the EPROM but it seems the company that offered the kits is long gone.

One of my pet peeves is construction projects that require programmed parts where the code is not posted somewhere. On several occasions I've built 10+ year old magazine projects and finding the code was always the hardest part. It's fun to build something vintage from scratch.

[ozcar]

I have that article on an Elektor DVD. There is quite a lot of software provided on the DVD for various projects, but not for that one, as far as I can see (I'm not really sure how the files are organised on the DVD, but I did try to search for it, and came up with nothing).

[amyk]

If you're just looking for an SCMS stripper, here's another one I found, with the EEPROM download:

http://www.rflab.pl/rflab_wp/scms-bit-killer-device-removal-security-bit-copy-protection-scms-eng/

[james_s]

Yeah I found that one too, but like I said I think he's already got a PCB for this particular one and also he likes the fact that aside from the code on the ROM it doesn't require any special ICs.

[zedstarr]

I realise I'm a little late to the party here... but did your friend ever find the ROM/contents? I've just pulled a load of my audio kit out of storage and found the Elektor SCMS stripper amongst it so I have the ROM sat in front of me.... but with no way to dump/read its contents.

Just quickly checked Amazon/eBay for USB/27C readers and didn't spot anything... is there an easy quick way for me to build a reader? I have breadboard and Raspberry Pi/BeagleBone and a few various flavours of STM32F dev-boards lying around   

If not I'm happy to send it to you/him be copied & sent back? EDIT: just realised you're in Seattle - posting it might not be feasible...

[CJay]

Did your friend ever find the ROM/contents? I've just pulled a load of my audio kit out of storage and found the Elektor SCMS stripper amongst it so I have the ROM sat in front of me.... but with no way to dump/read its contents.

Just quickly checked Amazon/eBay for USB/27C readers and didn't spot anything... is there an easy quick way for me to build a reader? I have breadboard and Raspberry Pi/BeagleBone and a few various flavours of STM32F dev-boards lying around   

If not I'm happy to send it to you/him be copied & sent back? EDIT: just realised you're in Seattle - posting it might not be feasible...

Manchester UK here and have the means to read the ROM.

You can however throw together an arduino EPROM reader and it wouldn't be difficult to do something similar with Pi, STM32 etc (but you would probably need to think about level translation)

[zedstarr]

Manchester UK here and have the means to read the ROM.

I'm just down the road in Southport ... 

[james_s]

Oh hey that's great, I don't believe he did ever find the ROM, I'd forgotten about this.

By odd coincidence the friend who is/was looking for this is in Manchester UK, and I'm pretty sure he's got an EPROM reader/programmer too. He's not a forum member but I can put you guys in touch if you like, or if somebody who can read it wants to post the file somewhere or send it to me I can pass it on and see if I can find one of those sites that collects assorted ROM images.

As far as USB readers go, the TL866 is pretty much the defacto standard for hobbyists.

[CJay]

Whichever works, I'm happy to help.

Zeddstar, yeah, not far but might as well be the US at the moment

Postage would work.

[zedstarr]

As far as USB readers go, the TL866 is pretty much the defacto standard for hobbyists.

Yeah I found the TL866 after a more thorough search - the TL866II being the latest variant it seems -  but at 62GBP (with fast delivery from ebay.co.uk) just a little too much for probably one-time use :-D

[zedstarr]

You can however throw together an arduino EPROM reader and it wouldn't be difficult to do something similar with Pi, STM32 etc (but you would probably need to think about level translation)

This was really bugging me, I haven't imaged a ROM for a long time and sending it in the post for someone else to read didn't seem right   

Based on the wiring & python I found here  http://www.myers-net.com/eprom/index.html and with the help of an old Pi Model 2B I've now got an image of the ROM 

(The referenced Pi GPIO wiring was OK, the python not so much - I had to considerably hack it around to get an actual binary image of the ROM    )

From the 7-8/1998 English language edition: "The data for the EPROM is provided by a small Pascal program that produces a binary file of 32768 bytes."

My image is all zeros after 0x7FFF - I think that's a good sign  :-)

[zedstarr]

I can confirm the Pi reading method is good - I bought a TL866II to satisfy my curiosity and it's just arrived. I've imaged the chip again with the TL866 and compared it to my Pi-derived image and they're both the same

Code: [Select]

$ md5sum elektor_scms_rom.bin
64bd11d7cd3a2ffcde307e94fd8fd679  elektor_scms_rom.bin
$ md5sum TMS27C512@DIP28.BIN
64bd11d7cd3a2ffcde307e94fd8fd679  TMS27C512@DIP28.BIN


[zedstarr]

For completeness here's an update on what I've managed to find out about the original article/author:

First published in most European language versions of Elektor 12/1997, English language version 07-08/1998
Author: Dipl.-Ing. Hans-Juergen Hanft (not credited with any other projects on Elektor) no contact details/records found
Georg Stippler - Stippler Elektronik, Bissingen Germany (suppliers of the kit/components) no contact details/records found
At the time the Magazine Editor was Len Seymour - has his name on some books of collections of projects that were published like "305 circuits" etc. but not much else
At the time the Technical Editor was Jan Buiting - he's now the Editor, still very active at Elektor and contactable on LinkedIn/Twitter or via email. I reached out to him and his reply was:

Very sorry but I have nothing on the project. Most project files and software carrier originals relevant to pre-2000 projects were discarded during a move of our labs and editorial offices, and several restructurings of the Elektor website and store.

Best I can advise is to issue a call for help on the Elektor Labs website.

So, I have registered a trial membership on Elektor's "Labs Website" and have asked there also ....

[zedstarr]

Another update:

Thanks to the clever people at the SonyInsider forum who have reverse-engineered the function of the state-machine from the original project article and the contents of the ROM along with the S/PDIF spec we now have some C, Tcl & Python code (attached in a zip file) that can re-generate the ROM binary image 

http://forums.sonyinsider.com/topic/30611-elektor-copybit-stripper/

UPDATE: [May/Jun 2021] the SonyInsider forums appear to have gone offline. Check the Internet archive/wayback machine link instead: https://web.archive.org/web/20210226125155/http://forums.sonyinsider.com/topic/30611-elektor-copybit-stripper/

UPDATE [Jun 2022]

Another ROM has been found in the wild and imaged:

https://github.com/andydoswell/Elektor-976516-1