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Old 9th May 2023, 9:57 pm   #41
Phil__G
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Default Re: Micro music box project.

The 48Z02 wasnt retaining and with its age I fully expected the battery to be flat,
But on these you can actually chisel the upper battery section off, it breaks away leaving (hopefully) two exposed contacts on the ram itself.
Divide and conquer!
I measured the cell - 0.4v which isnt bad after 35 years!
I then got a brand new coincell and soldered it backwards to the ram, and so destroyed it Ho hum. And it was all going so well...
Another one is on its way from the 'bay. The idea is to put the Twonky eprom contents in page 0, and use page 1 as ram, which allows the Aitken SC/MP to mimic the Twonky hardware. We hope.
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Old 9th May 2023, 10:15 pm   #42
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Default Re: Micro music box project.

Good luck!

This won't help, but I have discovered where ETI hid their mistakes and corrections: In the 'News Digest' section which is usually fairly early on in the magazine, but punctuated by adverts so you may have to look through 15-18 pages to make sure you have definitely read all of 'News Digest' in a particular issue.

The reason I say it won't help is that although I went right through 'News Digest' in all of the issues up until the end of 1979 and found quite a few errata for other projects, I found no further mention of Twonky.

I think Computing Today was up and running by this time, is it possible that they may have put any follow ups for the project in there instead?
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Old 9th May 2023, 10:47 pm   #43
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I can't shake the feeling that we will put a huge amount of effort into this, and it will (of course) eventually work, and we'll listen to it working for about 30 seconds and say:

"Right! What shall we do next?"
Yes its like you finally track down that toy you wanted as a kid on eBay and when you get it you realize it was actually a bit lame.....

At the time I started off on this I was just thinking of getting something that could play background music that wasn't specifically recognizable. As a frustrated musician of no talent I was intrigued to see what twonky sounded like....

I'd bought Pedro Kroger's book "Music for Geeks and Nerds" (https://www.pedrokroger.net/mfgan) and completely failed to get very far in my knowledge of music theory let alone any insight into how to make an "auto composer" or aything that produced listenable tunes. Its more frustrating because so many people in my family are musicians who have also failed to be able to teach me to play anything!
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Old 10th May 2023, 1:50 am   #44
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Well I've done some digging and found the sources I had. This source contains the patches from the Complement and Add to allow it to run on the MK14, with the original statements commented out.
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Old 10th May 2023, 3:28 am   #45
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Default Re: Micro music box project.

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At xxB5, ( Label: SIO1: ) there is actually an SIO instruction. With absolutely no explanation in the comments. This is another difficulty, the sometimes quite verbose comments often don't start on the line of code which is doing what the comment says is being done.
The article is one of the worst I have seen in ETI who normally did a pretty good job of it. I guess back then the editorial team didn't know enough about microprocessors to know if the author had done a good job.

Way back then the printing technology would probably have meant some typist was given a listing and told to typeset it so it could be pasted into the page, which is where all the errors crept in. Its disappointing there are errors in the hex listing because that is actually fairly easy to verify if you get a couple of people to type in the same thing and compare them.

Many projects I attempted to build from Electronics magazines back in the early had significant errors - especially with veroboard layouts, whilst if the PCB artwork was giving, this was generally more reliable (more so than the circuit diagrams - where many TV and computer manufacturers also had errors on these, due to primitive CAD that didn't link these via netlists).
I do recall once sending Everday Electonics 2 pages of the errors I'd found with their DMM project - even though it used PCB's. But they replied they couldn't contact the author, for comment, so I don't think they published any corrections. Apparently Elektor do build all their published projects in their own labs, for testing.

Oh the joys of spending hours over many nights, typing in magazine program listings back then - Only to be disappointed by the results from the magazine cover photos - If the program worked at all! Some magazines did try printing exact graphical copies of the printout from the computer, with no re-typesetting of it, to try to prevent errors creeping-in. But ZX-printer etc. outputs weren't the clearest to start with, so it could still be difficult to interpret exactly what should be typed (especially when odd-symbols like Commodore had on the keys).
Although at least with BASIC, it did teach you how to debug it / and often learnt how to program (or not) from this. However, you haven't got much chance with a hex-dump, without disassembling it (and ideally having a copy of the correct assembly-language source).
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Old 10th May 2023, 8:29 am   #46
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Default Re: Micro music box project.

Ian, thanks for the source of your version. It will be interesting to compare the differences, if any.

Owen: Sleepless night last night?

I had a light bulb moment and just did a general internet search on 'Twonky' which is such a unique word that I hoped it might find a youtube video of the original project working. No such luck, apparently there was a 50s SciFi series called 'The Twonky' and that, plus some kind of multimedia app of the same name gets in the way of any other meaningful results.

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Old 10th May 2023, 10:56 am   #47
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I had a light bulb moment and just did a general internet search on 'Twonky' which is such a unique word that I hoped it might find a youtube video of the original project working. No such luck, apparently there was a 50s SciFi series called 'The Twonky' and that, plus some kind of multimedia app of the same name gets in the way of any other meaningful results.
Yes, I spent some time when I was in hospital searching on my phone and discovered much the same.
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Old 10th May 2023, 12:06 pm   #48
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Well I've done some digging and found the sources I had.
Looks like you've put a fair bit of work in there Ian
I need to read and absorb if I can... my biggest hurdle is understanding the general principle, dividing notes, sub-tunes, highest notes etc
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Old 10th May 2023, 12:43 pm   #49
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If I get a chance tonight I'll do a side by side comparison between my and Slothie's ASM versions of the code as modified for MK14 by Geoff P. It would be great if they turn out to be line for line identical and produce identical code.
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Old 10th May 2023, 1:08 pm   #50
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has anyone with a MK14 tried it yet? as far as I can see it will run without the prsg but wont randomise...
This weekend I'm away camping at Old Warden (Shuttleworth Collection) so I'll take all this to read up properly No Mills & Boon here

Found this:https://www.youtube.com/watch?v=6sc4...GHKs70zE_MB_8K

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Old 10th May 2023, 1:19 pm   #51
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I once accidentally went past OW when there was obviously an airshow underway, but kept on going to my original planned destination... The National Museum Of Computing at Bletchley.

Hope you have a good time there (and the weather is kind enough to let the old kites fly).
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Old 10th May 2023, 1:34 pm   #52
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Quote:
as far as I can see it will run without the prsg
Can you make an educated guess as to what it will do with no stimulus from the noise generator? Play the same note, the same length, over and over again? Or something else?
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Old 10th May 2023, 1:41 pm   #53
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Default Re: Micro music box project.

and this:
https://monoskop.org/images/1/1a/Von...puter_1969.pdf
https://www.discogs.com/artist/154028-JK-Randall
...but nothing about an algorithm by Prof Randall that in any way aligns with the Twonky...

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Old 10th May 2023, 2:41 pm   #54
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Quote:
as far as I can see it will run without the prsg
Can you make an educated guess as to what it will do with no stimulus from the noise generator? Play the same note, the same length, over and over again? Or something else?
I'd guess something of the sort. You would hear something however. I would imagine you could just touch the SenseB pin to inject hum to get some variations.
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Old 10th May 2023, 3:16 pm   #55
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Default Re: Micro music box project.

Staying with TWONKY specifically, can anyone suggest which pins of the 4006 shift register IC are which, in the attached circuit diagram subsection? I mean specifically the four unmarked pins on the upper side of IC2.

The circuit write up says that the source input to the PRBS circuit is from NADS and that seems likely to go to the clock input of IC2, pin 3. The 4006 seems to be a bit of a building block IC with the possibility of 'assembling' the internal stages in a number of different ways.
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Old 10th May 2023, 3:33 pm   #56
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Aha, a very similar looking circuit here with the same arrangement of 3x XOR gates. Plus IC pin numbers and the interconnections between the individual shift register blocks which are omitted on the ETI version.

https://gr33nonline.wordpress.com/2018/08/19/lfsr/
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Old 10th May 2023, 3:34 pm   #57
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My guess left to right would be
Pin 6
Pin 9 and Pin 5
Pin 10 and Pin 4
(Pin 12 and Pin 1 connected together)
Pin 13
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Old 10th May 2023, 3:43 pm   #58
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Full marks, Mark See the diagram linked to in #56. I may just build this. The 4006 and 4070 (equivt to 4030) are £4.00 the pair plus post from Cricklwood. Not too heavy. There's just something in me that wants to hear this thing work exactly the way the designer meant it to, not just with any old random stimulus.
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Old 10th May 2023, 3:58 pm   #59
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I based the PRBS on the ortonview on this circuit from the Formant Synthesiser, with reference to other similar generators on other ETI and Elektor designs.
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Old 10th May 2023, 5:49 pm   #60
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Full marks, Mark See the diagram linked to in #56. I may just build this. The 4006 and 4070 (equivt to 4030) are £4.00 the pair plus post from Cricklwood. Not too heavy. There's just something in me that wants to hear this thing work exactly the way the designer meant it to, not just with any old random stimulus.
I just based the guess off the way the 4006 has blocks of 4 shift registers and single shift registers drawn as six blocks, then saw from the pinout that this was the easiest pin connections to route. You beat me by one minute, not enough time for me to cheat by typing the connections of the diagram you posted. Not sure how well that works for prbs 18, I have used similar circuit for prbs 9 or 15.
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