[sdiy] 8080-based synth reliability

[Ove Ridé]

I'm 32 and I've written self-modifying code for a CPU similar to the 8080.
(Namely the CPU in the original Gameboy, a Sharp LR35902, often incorrectly
described as a "Z80" when its ISA actually closer to 8080.) I suspect I
would actually be able to figure the code out from the binary.

On Saturday, 7 October 2017, Dave Brown <davebr at modularsynthesis.com> wrote:

> I’d have to look for the source.  Note it was written in assembler and has
> to execute out of RAM since it entails self-modifying code.   Those two
> facts may rule out anyone younger than 50.  I’ll see if I can dig up the
> code.  I might have it somewhere.
>
>
> Dave
>
>
>
> *From:* Ove Ridé [mailto:nitro2k01 at gmail.com
> <javascript:_e(%7B%7D,'cvml','nitro2k01 at gmail.com');>]
> *Sent:* Friday, October 06, 2017 1:08 PM
> *To:* Dave Brown
> *Cc:* Synth DIY
> *Subject:* Re: [sdiy] 8080-based synth reliability
>
>
>
> You ought to document the project for posterity and 5 minutes of Hackaday
> fame. If you post a ROM dump or perhaps source code if it survived for all
> these years, the project might take on a modern life on its own by
> dedicated hackers. (I for one wouldn't mind looking at it.)
>
> On Friday, 6 October 2017, Dave Brown <davebr at modularsynthesis.com
> <javascript:_e(%7B%7D,'cvml','davebr at modularsynthesis.com');>> wrote:
>
> This is definitely DIY related and somewhat synth related in that it is a
> digital 3 voice synthesizer.  In late 1976 I designed a dedicated 8080
> based three voice PWM synthesizer as a doorbell.  The code was based on a
> program called Music for the Processor Technology Sol-20 computer.  I had
> to disassemble the program to get it to run on a basic 8080 system using a
> single 2708 EPROM and two 2114 static rams.  It used a simple transistor
> driver for the speaker.  The 8080 is unmarked so I think it might even be
> an engineering sample.
>
>
>
> This system has continuously run for approximately 14,870 days or nearly
> 356,880 hours.  Well this week it died.  The processor is just absolutely
> lifeless.  I had another 8080 from the same vintage but at least marked and
> replacing it brought the system back to life.  Note that in the 40 years
> the 2708 has not forgotten even though the guaranteed retention is only 10
> years.  I think it will outlive me.
>
>
>
> It was a really progressive program for the time.  This doorbell also
> includes a RS-232 interface so I could compile new music to upload to it
> for special occasions.
>
>
> Dave
>
>
>
> David J. Brown
>
> Modular Synthesis, LLC
>
> http://modularsynthesis.com
>
>
>
>
>
>
>
> --
> /Ove
>
> Blog: <http://blog.gg8.se/>
>
> "Here is Evergreen City. Evergreen is the color of green forever."
>


-- 
/Ove

Blog: <http://blog.gg8.se/>

"Here is Evergreen City. Evergreen is the color of green forever."
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