Software for single chip computers etc. contained within products.

[Stephen Taylor]

Hi,

I’m considering buying a Beocenter 7700 which is a great price even though it’s not working.  I was wondering what people do when a software-containing component in a product stops working.

Is there a repository of software images contributed by people somewhere?  Apart from that the only solution I can think of is appealing on forums for users who might have spares.  I can’t imagine anyone would be keen on removing an eeprom/SCC from a working product and copying the image so that it can be used to re-flash a blank device.

Apologies if the answer is well known – I did do some searching before posting.

Cheers!

[artig]

As far as I’m aware there is no such repository, and doubt that even the B&O archive has copies of the software images.

There are a couple of potential problems:

1. The single-chip controllers are mostly mask programmed and it’s not possible to read the ROM memory from them.
2. There are no pin-compatible controllers with eeprom or flash memory available in most cases.

The Beocenter 7700 uses a Mostek 3870 controller (same as Beomaster 6000) which was not available in an EPROM version, but was available as a bond-out with a piggyback board where an EPROM (2716) could be mounted. I have one of these, but without the software image it’s not really of much use for these purposes. I don’t know if any lab samples or pre-production samples were produced with the piggyback chip.

I have heard of someone developing a replacement chip for a Beomaster 8000 using a completely different microchip (PIC, perhaps) on a small circuit board, writing a program from scratch. Someone else was planning the same for a Beomaster 6000 but don’t know if that ever came to fruition. The more usual option is to take a chip from a product which has died of other causes than a SCC failure.

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[Stephen Taylor]

Thanks very much for the reply – great details in there.

Although creating a replacement from scratch is really appealing to me, it a hell of a lot of work.  For me the hardest part would be reverse engineering the requirements.  Even so I’m tempted to see how far I can get with something like a BBC microbit and a Heath-Robinson DIL adaptor.

Cheers

Steve

[T.W.G]

Actually somebody has done some cloning of the old Bang & Olufsen Eproms for repair, backup, replacement:

https://github.com/theretrobristolian/B-O-Software

[Stephen Taylor]

Fantastic – that’s worth knowing!

Thank you!

[artig]

The service manual is an invaluable aid in reverse engineering the requirements, and most of it could be done using that.

Also there may be some information to be found at https://beomicro.wordpress.com which could be helpful. Including contributions from some of the people who worked on the original development.

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