Project ACG

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superryan94
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Location: Rotterdam The Netherlands

Project ACG

Post by superryan94 »

As I got more and more interested in space and the old tech used there I decided to build one of the marvels of the old times with Logic Circuit.
I got my hands on all the drawings of the Apollo Guidance Computer and decided to make the logic part here.
The logic part consists of 24 modules build using only 3 pin NOR gates. Each module has 284 used and unused pins.
Most of the drawings I can copy one to one, but some things are a bit incompatible with this software and for that I need make a work around by not including all parts(I exclude part that cause errors in the program and looked like just signal enhancers) and adding OR gates where multiple signals went to the same wire.
Also, the original AGC did not have a databus system like I use, but rather direct connected wires. That would however give such a big mess in my drawing that I decided that it's not worth it and choose for the databus for pacticalness.
As such, what I make is only 95% accurate to the real thing.

Here I have the first 3 modules build. More are on the way and I'd like to see where this end up in terms of level of interface.
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admin
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Re: Project ACG

Post by admin »

Take it to the moon.
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superryan94
Posts: 53
Joined: Sat May 09, 2015 5:59 am
Location: Rotterdam The Netherlands

Re: Project ACG

Post by superryan94 »

It's already been over 2 weeks I last posted something, so time to make an update on progress.
Between work and other things I have to attend to in life I place some NOR gates or draw some lines.
Today I spend 12 hours on making the last part(everything for the ports above 400).

I also looked it I could use this to design the circuit boards I need, but it's 71 pins wide and I need 85>.< (Traces of doing that are still in my draftboard)

Also made a main data bus to reduce the amount of wires going around, looks a bit neater now^^

It's a lot of work to draw it, so progress is slow.

Also, could I get the option to highlight wires? At some points I got lost in the wire mess that arises when I work and that added over an hour of extra work:/
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admin
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Re: Project ACG

Post by admin »

Nice progress. It will be easier for you if you start to wrap up chunks in separate circuits. With smaller circuits you don't need wire highlights and much easier debug and navigate.
Keep it up
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superryan94
Posts: 53
Joined: Sat May 09, 2015 5:59 am
Location: Rotterdam The Netherlands

Re: Project ACG

Post by superryan94 »

Small correction, forgot to connect some things.

It's pretty hard to make the circuits smaller with the drawings I have.
And the point that gave me a lot of trouble was this. At first it looks pretty easy, but at some point I couldn't see what goes where in one go anymore....
Image

For debugging I use excel. I have all the ports with identification for both on the circuit ports and the data lines. This saved me over 10 hour of looking for errors as I simply have to isolate the wire making the error and check both sides of it.
Image

And one last thing for when I'm finished, would it be possible to run an ancient piece of code in here to test the circuit?
https://archive.org/details/aurora00dapg/mode/2up <--- is also where all the drawings, manuals and data is to find about the computer.
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superryan94
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Location: Rotterdam The Netherlands

Re: Project ACG

Post by superryan94 »

I'm starting to get some difficulties in my circuit now it's getting bigger.
The first one is that the amount of signals going to and from a circuit is getting pretty big and since they come out of a splitter I need a lot of space for them. I kinda have a solution for that which is removing a few signals that are no longer in use to compress the databus size a bit and having a "mini bus" circuit containing the splitter part but it's a lot of work and can introduce some more bugs.
Second thing I now have is that my circuit speed is dropping considerably when there is a "load" attached to my circuit. The led array which is easier for me to read limits my frequency to 12.8 and the sensors to 16.6. I need this load because if I do not have it my circuit will oscillate.
Is there something else I could use as load to keep my circuit stable?
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superryan94
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Joined: Sat May 09, 2015 5:59 am
Location: Rotterdam The Netherlands

Re: Project ACG

Post by superryan94 »

Got the 5th part finished. only 19 left to go.
Added a Databus Compressor to go from 31 to 14 signal sets.
This also greatly improved the stability and speed.
Still no inputs for you to press on sadly though....
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