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MIDIbox TIA - Atari 2600 Synth


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  • 2 weeks later...

Hi all,


I am still trying to get my head around this midibox stuff and wondered how you implement the LED meter? Is it an LTC module connected to the core? Also how many LEDs are supported?


Atari is on the way :smile: I just need the info on this before I order the parts. Thanks in advance for your help.

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  • 2 weeks later...

hi Thumper,

Led bargraph is not real one, i mean this is not a sampling and integration of the audio signal, there's two volume registers in the TIA drived by the PIC, i just use this value, one bar by register with 4 thresholds which lit the leds.
This Volume (AUDV0 and AUDV1) registers are 4 bits, so 16 level.
for each register so:
first led on when 0x01 =< AUDVx <0x07

first, second led on when 0x07 =< AUDVx <0x0b

first, second, third led on when 0x0b=< AUDVx <0x0e

all led on when 0x0e=< AUDVx

inc file attached

led handler is called on AUDVx change.

Simply that's all


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  • 3 months later...
  • 1 month later...

Has this project gone dormant? Still think this is the 'missing link' in chip-synth history, along with the STERN and WILLIAMS 80's sound boards

Just don't have the time and my job push me very far from my home. For example, now I'm in Tanzania and I'm French.

I know everybody is waiting for me, please be patient, life is not an hobby.
Two of my own friends are waiting for this since a long time, sorry for that.
Some link are missing for sure but it's not a fake one, Ephteca can tell it, I sent a full kit to Thorsten too, but I think he didn't take the time to build it, maybe he has a job too ;)

I promise that i will continue this project, this is a priority for my next holidays.

The list
- Mat x1
- Djo x1

- Mrspring
- Yogi
- Scrubber Fox
- Thumper
- Academic Planner

- Me x3

Best regards


Edited by Antichambre
forget a detail
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I didn't share the firmware on the SVN, cause I was not be able to do it, forget password now I think, key files are probably lost on my older dead computer. Sorry... toDo
Sources are structured and FW is running but have to check if they are clean and readable, that's ASM...
I remember Wavetable(like SID) and 4bit Sampler Modes have to be fully tested and implemented.
All others things are on dokuwiki.
Note: after some tests I think PIC is not enough for 4bit Samples memory (10 sec max)

I have a lot of work that's true, but not only. My biggest problem, it's like the tracks I made, always feel it unfinished, like an uncompleted thing, don't know if it's just because I'm never satisfied or because an idea is always introducing more ideas, but it's an infinite thing...

So I've got a lot of thing to do with the TIA and I spent some time to develop and test some.
You know that the 'T' if TIA is Television?
So this chip can generate a video signal too, that's the raison i tried to connect it with a LPC17. Because video needs a fast uC.
I used the internal DAC with FFT routine and an external audio source to modulate different patterns.
Here the result:
Circle diameter change on Background luma change.
Reel time Spectrum Analyser

What i want is a Midibox with 4 TIA and 2 POKEY for audio to expand voices and a separated TIA for the Video part.
Of course we need a dedicated CS for this machine too.

But i cannot do it alone, it's too much work. I will finish the little cartridge for those who want it, and after if someone is interested to help me develop this bigger project he's welcome, I can share everything.



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  • 3 weeks later...

Ahh!! Antichambre!! He lives!! :)

Yes, i fully understand, life and REAL job take preference over things like this project. I also enjoy/dislike this situation. But, the job will enable You to be comfortable and do things the way YOU want to do them, then when You finish, You can look back without regret at what you did. So, take Your time, and keep looking forward to hearing Your machine in people's music. There is no deadline here.

Also, I understand also 100% about making music, and never being happy because You think it is never finished. In the days of the indie electronic record business (1982-2005, RIP) We had a Label, A&R, budgets and deadlines. This was why projects were finished and sent out. This is not the case now. I know many people who make excellent music, but they over-think it, over-produce it and ruin it because they have no deadline or target, and they just keep messing about with the tune, never doing a final mix or render because they think it can be better, then they abandon it because it has lost the initial spark. Such a shame :( I say - be brave, if a tune makes You *feel* something - STOP MESSING WITH IT AND MIX IT DOWN :) How many tunes do You love after 10,20,30 years that are simple and raw? I bet many many.

Also(2), Tanzania! Wow.. OK. well, greetings from Ireland, where it has been raining since 1989 :)

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  • 2 months later...

the pictures in the gallery are only tumbnails (because of Website Moove...), so i cant see much details

stupid question, catrige version means?

a. i need a atari to plug it in - to get it running.

b. it has the size to fit into a catrige - and it has not to be pluged in a atari..

because i have a TIA but no Atari


if b. PUT me in please. thx phat


Edited by Phatline
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Hi Phatline,
For Gallery, I've got the same problem as you but i find that you can see it with right click on the picture and open in a new tab, strange behaviour...
Can not delete a picture too... Hummm.
No VCS needed, the PCB fits into a cartridge, there's all I/O on a D-Sub 25... Power, MIDI I/O, Audio L/R and Aux for tuture purpose.
It's a standalone synth, you just need to drive it in midi and/or with the manager I created under Max/Msp.
See wiki for more explanation and detail, you will find a video of cartridge in play ;)
Then, You're in the list now ;)


New list:

- Mat x1
- Djo x1

- mrspring
- yogi
- scrubber
- thumper
- Academic Planner
- Tr1ptron1c
- Phatline

- Me x3

Edited by Antichambre
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  • 8 months later...

Hi everybody,

I'm sorry for the wait, some of you would not believe it.
But. Here we are!
You will find on the
wiki all the "Cartridge" completed.
Some of you will find their nickname in the
bulk order list.
If you still wish it, complete the options if not erase your line.
And I will calculate final price for each one of you asap.

Best regards


Edited by Antichambre
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Hi Phatline,

4 hours ago, Phatline said:

cool! phat documentation

Thank you, did my best with my best English.


6 minutes ago, Phatline said:

ok so can we talk about to source the chips... not that we bid against us on ebay :rolleyes:

I checked ebay price and they are thief.

You've got 2 solutions;
1 - I know the guy, his parts are original, he is in California.
He can provide the NTSC and PAL model
TIA NTSC (separated outputs) 11$50
But he limits the quantity by order, because it's an old and original stock. He is an historical Atari spare part provider.

2 - Psykhaze found a chinese source for the PAL model UM6520P1, he already sent me some, I tested it, and it's fine, same as original I have got.
We can try to deal it 4euro each and we are close to order 50 pieces.

Then source the chip is not a problem, just tell us how much you want. ;)


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