Acorn Electron Sound Expansion Cartridge

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gazstone
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Acorn Electron Sound Expansion Cartridge

Post by gazstone » Sun Jun 19, 2011 10:26 am

Hi.

I know this is probably a long shot as I believe they are quite rare these days.
I am trying to find a Sound Expansion Cartridge for my Electron to enable the playback of 4 channel sound as on the BBC Micro.
Any help would be gratefully appreciated :)

Thanks,

Gareth

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Dave_E
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Re: Acorn Electron Sound Expansion Cartridge

Post by Dave_E » Tue Aug 09, 2011 6:26 pm

I've been searching for one for 15 years. ;-)

Prime
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Re: Acorn Electron Sound Expansion Cartridge

Post by Prime » Tue Aug 09, 2011 6:52 pm

Does the schematic for one exist ? or one that I could borrow and trace, perhaps
we could produce a reproduction ?

I'm asuming of course that this uses the same sound chips as the BBC.

Cheers.

Phill.

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SarahWalker
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Re: Acorn Electron Sound Expansion Cartridge

Post by SarahWalker » Tue Aug 09, 2011 7:19 pm

It's not a complicated cart, you could probably reproduced it easily. Sound chip is an SN76489, same as the Beeb, with data at $FC98, enable at $FC99, ROM at $8000-$9FFF, RAM at $A000-$BFFF (probably 2k mirrored). The ROM image is included in Elkulator.

It's also properly buggy, with issues with quite a lot of games.

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aerworuld
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Re: Acorn Electron Sound Expansion Cartridge

Post by aerworuld » Sat Oct 06, 2012 2:15 pm

Picking up on this thread, has anybody come across an availability of any of the sound expansions for the Elk? I seem to remember reading a review in EU magazine of a device that was essentially just an amplifier with a volume control and a jack for headphones..

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jms2
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Re: Acorn Electron Sound Expansion Cartridge

Post by jms2 » Sun Oct 07, 2012 8:17 pm

What is the RAM for Tom? I would have expected it to use the same memory locations as the BBC - which I assume are still spare in the Electron's main memory. Or does it use that space for something else?

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danielj
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Re: Acorn Electron Sound Expansion Cartridge

Post by danielj » Mon Oct 08, 2012 11:30 am

I assume the RAM's workspace for the ROM as the Elk doesn't have the gubbins to drive that sound chip natively. It wouldn't be too hard to knock one of these together, but it'd use up a valuable cartridge slot....

d.

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Slo
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Re: Acorn Electron Sound Expansion Cartridge

Post by Slo » Mon Oct 08, 2012 12:07 pm


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Pernod
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Re: Acorn Electron Sound Expansion Cartridge

Post by Pernod » Sat Jan 27, 2018 3:56 pm

Did anyone ever find one of these cartridges?

There are two known versions:
v1.00 from Project Expansions (1988) by D.Ingleby-Oddy
v3.00 from Complex Software Systems (1989) by D.Ingleby-Oddy

The v1 contains 8K RAM and apparently has a jumper to move this RAM to the other page 'Move jumper to RAM position and press CTRL+BREAK', instead of from $A000-$BFFF in same page as 8K ROM. It also provides *LRAM to use this sideways RAM.

The v3 ROM doesn't mention the RAM so assume it's permanently at $A000-$BFFF in same page as ROM. The v3 ROM image is 16K but second half looks like RAM workspace so should probably be trimmed down to 8K.
Attachments
sndexpc.zip
v3.00
(3.74 KiB) Downloaded 11 times
sndexp.zip
v1.00
(4.48 KiB) Downloaded 15 times
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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jms2
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Re: Acorn Electron Sound Expansion Cartridge

Post by jms2 » Sat Jan 27, 2018 5:29 pm

I have always been a bit intrigued by these cartridges. They must be incredibly rare.

Those roms seem to contain quite a lot of junk data though - the v1 version seems to contain some EPROM programmer code, and the v3 version has some assembler in it (I mean assembly language text, ie source code). I guess the actual hardware requires very little support code.

A bit of googling has revealed that the chap who designed it (David Ingleby-Oddy) is very likely to be a director of this company. I wonder if he's kept the schematics?

EDIT: I've emailed him. I'll let you know whether I get a reply.

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Pernod
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Re: Acorn Electron Sound Expansion Cartridge

Post by Pernod » Sat Jan 27, 2018 7:10 pm

jms2 wrote:A bit of googling has revealed that the chap who designed it (David Ingleby-Oddy) is very likely to be a director of this company. I wonder if he's kept the schematics?

EDIT: I've emailed him. I'll let you know whether I get a reply.
The name is quite unique, hope he replies.

I now have v3 in MAME and sounds quite good with some of the Byte the Apple demos. http://www.acornelectron.co.uk/mags/eu/ ... -soun.html

I kinda expected the v1 ROM to require similar hardware, but it has the SN76489 data at $FC84 and enable at $FC85, whereas v3 has data at $FC98 and enable at $FC99. This doesn't sound anywhere near as good as v3 so not sure if I have it right. The review at http://www.acornelectron.co.uk/eug/revs ... e_000.html suggests maybe I shouldn't expect too much.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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