Reference Manual
Castle 000 ADC
Technical documentation, setup guidance, and patching workflows.
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Archived community reference. This page compiles related LZX Community forum discussions for Castle 000 ADC inside the new documentation site.
Related discussions are compiled below.
Community Discussions
Fortress Dev Blog August 2018
I’d like to talk a little bit about Fortress, where it comes from and where it’s going. The concept for Fortress started to form as a back and forth with Lars. Lars had been suggesting a ‘best of Castle’ module – something that was a collection of my favorite patches. Lars got me in to CPLD, which is a huge array of logic gates that you can program. After much mucking about I got the Xilinx suite installed on an old laptop. For some reason the software didn’t like my desktop PC, and every time I tried a new install it would just crash. No Joy. I got a dev board from Lars for the CPLD. I started programming the core for a Video Weaver style thing. This is where some ideas really started to form.
The Castle series is very concise in it’s format. 4HP panel width, a maximum of 8 jacks, a maximum of 2.25” depth, and through hole parts, so all the modules had to be designed with that in mind. With a larger format module we could have more complex operations and greater circuit density with SMD parts.
Lars asked me to come up with a panel mock up for a proposed Super-Castle. Since I am completely incapable of using Illustrator I came up with this:
I know, I know…
Derek Holzer posted some pages from a book on the Vasulkas, it had some images from a digital image processor they had made in the 1970’s. It was Some Analog to Digital Converters (ADC), an Arithmetic Logic Unit (ALU), and a Digital to Analog Converter (DAC). I believe it was 4-bit, but besides that, it was very ‘Castle’. I was aware of the Vasulkas work with computers in the 1970s, and this was definitely one of the inspirations for Castle, but I hadn’t seen the stuff with ALUs shown in such a way. This really inspired me. You could combine two digitized signals in really interesting and non-linear ways. So with this in my mind, and the Weaver concept, I started to come up with some block diagrams of modes that I thought would make up my perfect incarnation of an all enclosed Castle. Some of the ideas were the Weaver, an ALU, and a 3*64-bit shift register. All of these modes include Clocks and Waveform Generators so the module can be used by itself as a pattern generator, and ADCs to input signals to control or be used as input signals like the Waveform Generators.
The Video Waver is inspired by Stephen Becks Video Weaver, as seen here
The ALU is inspired by the work of the Vasulkas in this area.
The 3*64-bit shift register is based on my work with the Castles. If you think of the shift register as a bucket brigade, you put a signal in the input and 64 clock cycle later you would get that input at the last tap. It will only let signal in on the start of the clock pulse so it also provides a quantization effect. If you were able to select which tap you were viewing on you could shift the image horizontally. Of course this selecting can be done at video rates, so some real nice wiggles can be made. The registers are 3-bits deep, so you can wiggle a video signal split up in to 8 zones of brightness.
This is the block diagram I came up with to try and illustrate what Fortress could be:
Something I really wanted to do when I was developing concepts for Castle was a Palette swapper. Something you could input your 3-bit values in to and it would assign those 8 values to color values that weren’t just combinations of full red, green, and blue. Something that could give you brown, pink, grey, whatever. Unfortunately the number of inputs and PCB size prohibited this from being a Castle module. But now with Fortress this can be implemented. That’s where the CGA palette comes in. Lars and I are both huge nerds, obviously. We grew up playing computer games. The CGA was a weird thing. It wasn’t designed for gaming really. It was designed for high contrast text like on spreadsheets and stuff. This made for some interesting color choices. Some people hate them, some people might love them. I love them. If you are unfamiliar, there are basically two palettes in CGA, and a half brightness variant of each. The palettes are: Black, Cyan, Magenta, White, and Black, Yellow, Red, and White. The Half brightness variants would make Dark Cyan, Dark Magenta, Grey, etc. A funny thing that IBM did with RGBI monitors, which were used to display CGA was that what would be Dark Yellow would be interpreted in the monitor as Brown. This is something that will be replicated in Fortress, as it’s just a funny thing. I like funny things like that.
Well, that’s all I have to say for now.
I’m open to questions if you’ve got any…
Thread Replies
Loving how this forum is developing into a wealth of various behind the scenes insights.
Thanks
I couldn’t agree more. All of the behind the scenes information is extremely inspiring and helpful for folks like myself with limited video experience.
. can’t wait to see this in action! 
. i’m a big fan of the retro feel as well - have you seen this video on CGA ? as an apple/mac guy, i had no idea how pc video standards worked. i found the history fascinating.
My first CGA memory.
Looking at the rendering on the main product page, it looks like the only inputs are the VC inputs horizontally across the top. Is that correct or am I reading the markings incorrectly?
yes, thats correct. there are 3 vco cv inputs, and 3 adc inputs. the adc vc inputs are what you would use to input camera signals and such in to.
Can’t wait to take some full color RGB footage for a walk into this digital territory.
I can’t wait to see some CGA goodness
I’m pretty sure this will be my first LZX module. Along some necessary utilities, of course. It sounds/looks awfully interesting, as do all your modules, @pbalj! Can’t wait for the demos, and for the Fortress to ship.
Cheers,
Lukasz
fortess will be a blast I’m sure
I’ve got to get some funds together here to pre order
RIBBONS 3-Bit Digitizer Discussion
https://lzxindustries.net/products/eurorack_modules/gen3_series/ribbons
Ribbons is a 3-bit digitizer module for your EuroRack video synthesizer. Slice your video sources and waveforms into eight discrete bands which invoke the look of primitive digital graphics and video colorizers from the 1970s and 1980s.
Implemented with 9 high speed analog comparators and CMOS logic, the digitization technique employed by Ribbons lack any pixel clock or quantized time base. This reveals a surreal and silky quality to the image under modulation, which we feel is absent from modern digital video.
Features
- Hard edged binary 3-bit ADC and Window Key outputs
- Positive and negative 3-bit DAC outputs provide stepped analog waveforms
- Center and Span controls and CV inputs allow modulation of sampling offset and scale
- Enable and Disable inputs extend utility for masking and compositing in the patch
Legacy
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Our first 3-bit digitizer module was 2012’s 8 Stage Video Quantizer & Sequencer, which was loosely inspired by the Amplitude Classifier module from the Sandin Image Processor.
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In 2018, we released Castle 000 ADC and Castle 001 DAC as part of the Castle DIY module series
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In 2019, we released Fortress, the first module to integrate ADC and DAC capabilities in the same module.
Specifications
- 8HP EuroRack Module
- Powered via 12V DC barrel or EuroRack power header
- Max Depth: 32mm
- +12V Power Consumption: 120mA
Thread Replies
Facebook question:
I’m guessing the lower left jack (arrow) is the input to be digitized? And D0, D1, and D2 are equivalent to the similarly named outputs on the Castle ADC. And I’m guessing that Center and Span are equivalent to Bias and Gain from the Castle ADC so the CV inputs are CV controls over that. But what do the other jacks do (EN, ~EN, ramp up, ramp down, and key)?
Lars answer:
You have the input and D0-D2 output correct. The center & span controls are a bit different. They are a new analog CV processor design with thru-zero modulation of span. The outputs of this internal circuit generate upper & lower thresholds. The area between the upper and lower thresholds is sliced into 8 equal bands, and then encoded to a 3-bit number. When Span goes negative, it inverts – allowing you to create ADC patterns that compress and expand under modulation (to do this with Castle or Fortress, you needed external VCAs). The Ramp up/down are DAC outputs (stair step waveforms) and the Enable/Disable inputs are video rate masking inputs to enable or disable he outputs (so it’s like having a compositor built in, so that you can combine or exclude the outputs from an external key/mask source.)
Facebook question:
How would you say this fits into a setup that already has Fortress in it?
Lars answer from FB:
Ribbons has some more advanced features than the Fortress ADCs, and focuses just on the ADC/DAC part of the workflow.
Lars answer from Discord:
Ribbons should play great with fortress and castle in the same way [as Castle and Fortress work together]. Castles are discrete functions. Fortress encapsulates a full voice. Ribbons encapsulates a component of a voice, it is a complex function with driver circuitry and voltage control.
In patch context, Ribbons is the first way in Gen3 to generate a 3-bit number. Other modules will receive 3-bit numbers. Together, that’s how you achieve Fortress style patches in Gen3.
wah, can’t wait for this! I love that early digital look
Really keen on this. Looking forward to a demo video.
There should be a stream on the LZX Twitch account really soon that’ll be Ribbons centred.
If you’re not on the LZX Discord, I recommend joining as it was announced on there. A couple of people have received their Ribbons orders already but I haven’t seen anyone post any video on there in the Gallery channel.
I am, thanks Robin:)
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