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• Receiving the Parts -- First Mail Package

  Blair Vidakovich • 03/18/2024 at 06:16 • 0 comments

  MC6800

  the CPU. the motorola MC6800. once quite popular, but somehow overlooked a little, imho, with the retro computing revivial of the 2010s. it runs lots of operating systems, like CP/M, FLEX, and more.

  this is the original chip that the 6502 team decided to try and radically simplify with their design. they were right. the 6502 reigned supreme.

  MC6875

  this is the 6800's external clocking logic. if you csn get one, your life will be easy. it will do all the clocking really well. this is an exotic chip now, however. ngl, at the price i got this, i will be hoarding them.

  this fits into the main cpu subcircuitry. we just need to get some passive components and then a 4 MHz crystal.

  -

  DMA Video Logic

  -

  
  

  these two lil buddies are the CD4014, and CD4040, respectively.

  they do the main clocking and signalling for the composite out video.

  the 4014 is a parallel in serial out shift register or buffer register. then the 4040 is a binary counter. you get the idea.

  please refer to the DREAM6800 schematics.

  these chips allow us to do DMA graphics @ 64 columns by 32 rows as a dot matrix.

  256 bytes of RAM in the DREAM's memory map are simply pixels in RAM

  Miscellaneous

  -

  1. a now very exotic LM566. not a 555 it's a really interesting VCO. voltage controlled oscillator. not surprising, it's from the digital audio in ciruitry. HAM lovers watch this space.

  2. some glue logic: 74ls123 and 74ls40.
  

  3. 10 x LM741s, lil cuties. they're ancient now.

  4. the power ICs.

• Sourcing Parts

  Blair Vidakovich • 03/07/2024 at 21:52 • 0 comments

  Please find below a suggested method for sourcing the parts for a small run of the device:

  ;----------------
  ; Integrated Circuits
  ;----------------
  
  | U1         	MC6800		https://www.aliexpress.com/item/1005004479143065.html
        
  | U2         	2716		*** AT28C256 ALREADY ON HAND
          
  | U3,U4		6116		*** UT6264CPC-70LL ALREADY ON HAND
         
  | U5,U6         74LS367		https://www.ebay.com.au/itm/392646329463
       
  | U7         	CD4014		https://www.aliexpress.com/item/1005006007339909.html
        
  | U8         	MC6875		https://www.aliexpress.com/item/4000045848422.html
       
  | U9         	MC6821		*** MOS6522 ALREADY ON HAND
       
  | U10        	74LS10		https://www.ebay.com.au/itm/124270171410
        
  | U11,U17	74LS04		https://www.ebay.com.au/itm/334703255973
        
  | U12        	74LS08		https://www.ebay.com.au/itm/234861194857
        
  | U13        	CD4040		https://www.aliexpress.com/item/1005006389797996.html
        
  | U14,U15	74LS93		https://www.ebay.com.au/itm/234860939045
             
  | U16        	74LS20		https://www.ebay.com.au/itm/392646331384
        
  | U18        	74LS11		https://www.ebay.com.au/itm/234868819629
        
  | U19        	74LS123		https://www.aliexpress.com/item/1005005071495170.html
       
  | U20        	7440		https://www.aliexpress.com/item/1005005805134654.html
          
  | U21        	74LS74		https://www.ebay.com.au/itm/234862799526
        
  | U22        	74121		*** ALREADY ON HAND
         
  | U23        	LM741		https://www.aliexpress.com/item/1005006103890733.html
         
  | U24        	NE566		https://www.aliexpress.com/item/1005006022531540.html
         
  | U25        	74LS138		https://www.ebay.com.au/itm/184350879253
       
  | U26        	LM2576-5.0	https://www.aliexpress.com/item/1005005877381901.html
    
  | U27        	LT1054		https://www.aliexpress.com/item/1005005658624513.html
  

• Project Concept Formalisation

  Blair Vidakovich • 03/02/2024 at 02:16 • 0 comments

  Who?

  "The Committee"

  • 50hz

  • shufei

  • vidak

  Yes you can join the committee.

  What is a permacomputer?

  A permacomputer is a computer which attempts to embody the virtues of permacomputing.

  Foundationally, permacomputing itself is set of community practices and traditions which shares a set of social and ecological values inspired by the 70s land management and settlement design of permaculture.

  What is the point of this project?

  The people's permacomputer project is an attempt to physically realise a permacomputer.

  This will involve not just the production of an actual model permacomputer, but also the development of a list of suggested social and cultural practices around computing that will, it is hoped, assist in the continued human practice of electronic computing.

  There are many different dialectical approaches to making an introduction to the people's permacomputer. One thought experiment that has proved especially popular and easy to grasp sums up the mindset behind which we are functioning:

  Industrial society has collapsed. All semiconductor fabrication has ceased, society-wide electrification is no longer guaranteed. There is no longer any internet. Computing as it was once known in the early 21st century is impossible. You need a computer for a task. What do you do?

  This project is a humble response to the challenge posed by the above problem.

  Adventures in the traditions of computation

  We seem to take it for granted that a computer in everyone's hand just is democratic computing. Indeed, the ubiquity of contemporary computation has been confused for 'democracy'.

  As quickly as we marched towards computing for the masses, we marched just as swiftly away.

  GNU

  There do today however still exist flourishing movements which are worthy of mention--although not exclusive in this honour, much of the GNU movement is to be credited with any sanity being preserved in present-day mass computation.

  Hobbyist computing

  The hobbyist computer movement of the 1970s was rich in ideas, and courageous--sometimes breathtaking--in its efforts to allow the lay person to realise their access to an electronic computer.

  Need we speak of the heterogeneous array of kit computers and their attendant clubs and magazines? Some of mention are entire influential computing platforms in their own right:

  • Altair 8800.
  • Apple I and II.
  • Commodore 64 and the VIC-20.

  From minicomputers to microcomputers

  One may even be able to recount the history of computing before its entry into the mass consciousness. Computer architectures from (now defunct) firms like DEC (Digital Equipment Corporation) still carry enormous significance today.

  Much of DEC's fascinating and progressive work culture is imprinted on the fruits of their labour. Two models of computer from DEC in particular, the PDP-8 and the PDP-11, are steeped in the corporation's ethos: "do the right thing".

  Neither of these machines were of much relevance outside the academy and industry, but they represent huge strides forward in human history for the virtues that the people's computer committee see as necessary for permacomputing.

  In particular, the full plans and maintenance manuals for each token computer were accessible alongside each physical device:

  http://www.bitsavers.org/pdf/dec/pdp8/

  http://www.bitsavers.org/pdf/dec/pdp11/

  When was the last time the entire structure of a modern smartphone was exposed and made accessible to the user? Indeed, the devices we take for granted today are deliberately obfuscated for the purpose of unchecked economic profit.

  Mutual exclusion

  There are many influential projects which attempt to address the same set of values driving the people's permacomputer project. Some worthy of note can be listed in no particular order:

  • Collapse OS.
  • uxn.
  • The RC2014 computer kit.
  • Ben Eater's 6502 project video series.

  All of these projects are concerned with some subset of the principles the permacomputer project holds dear....

  Read more »

• February 2024 Update

  Blair Vidakovich • 02/20/2024 at 21:15 • 0 comments

  In our exploratory research we came upon an australian design from the late 70s which i think would prove highly amenable to the goals of our project.

  http://www.mjbauer.biz/DREAM6800.htm

  Attached is a bill of materials along with other errata from a fellow peer's construction of the DREAM6800 computer in 2019. 

  (see attached PDF)

  I am having difficulty sourcing parts. I laboriously inputted and was able to locate every part on aliexpress, but multiple items from the same vendor would not cause a saving in the postage.

  Does anyone know a more equitable method of sourcing the parts listed in this PDF?

  Much appreciated.

  Blair Vidak.

  ---

  Please find reproduced below the schematics for the DREAM6800 computer.

  Power:

  -** Cassette circuitry. Kansas PSK encoding.

  - *** CPU and Clock generation via the Motorola 6875:

  ** Video Display Generator (composite video):

  The keyboard circuitry, implemented by the Motorola PIA:

  Current smoothing capacitors and auxiliary circuit definitions:
  

  Memory:

  ---

  The full listing for the CHIPOS interpreter / monitor program resident in 1K ROM:

  **

• Video Teleprinter

  Blair Vidakovich • 05/25/2023 at 13:52 • 0 comments

  (this is in collaboration with a comrade 'S')
  

  The People's Permacomputer Project (acronym: P3) is designed to meet a special design case. That is: modern digital civilisation has collapsed. Complex computer hardware is hard to come by, and will not be easy to repair. This hardware project will also attempt to meet a use case scenario: storage upwards of 200 years, and be durable enough to still operate.

  It is my hope this permacomputer will truly be able to last around 500 years with minimal need for maintenance or repair.

  ~The Nipkow Disk Video Teleprinter~

  Please refer here. the hellschreiber is a shortwave radio compatible facsimile device. In other words, the hellschreiber is a type of radio fax machine.

  The principle behind the radio fax is similar to a mechanical televison. Instead of using ink to print onto paper, the television uses a nipkow disk to scan across a flashing light source, such as an LED or fluorescent tube. The flashing light is timed to the position of each of the holes in the nipkow disk, allowing luma pulses to be created, mimicking pixels on an electron-beam CRT.

  ~Construction of the Mechanical Video Teleprinter~

  The first movement of this project is to design a mechanical television. This stage of research and development will be considered a success if an operating 30-scanline nipkow disk television can be built.

  Why? Because video is important for the human-computer interface, and resources will be severely limited in terms of what will be able to provide a standard, as well as modular interface into the digital logic of the P3.

  The mechanical television is a good choice for demonstrating the possibility of video output from a digital computer after the collapse of modern society.

  Please find attached the research material from the Ben Heck show.

  Episode #1

  
  

  Episode #2

  Suffice it to say: you construct a 30 line televisor @ 15 FPS with the following materials:

  - a cheap electric drill
  - some vinyl LP records
  - a cheap LED or fast fluorescent light

  This construction is a happy congruence with the processing limitations of the digital computer to which the mechanical TV will be attached. It will only be capable of 30 scan-lines of resolution.

  Please refer to the reference images of what i imagine this mechanical TV will be able to render.

  Up Next Time: Ceramic DIP 8-bit CPUs (:

  http://www.mjbauer.biz/DREAM6800.htm
  

  https://maggi9295.github.io/projects/dream6800/dream6800.html

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