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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Preview of the ALU card.
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ALU20.jpg [ 33.69 KiB | Viewed 7361 times ]
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| Fri Oct 20, 2023 5:07 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Now 24 bits. .750 us core cycle 1.5 us Memory cycle 1974 74xx & 74Hxx
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alu24.jpg [ 31.68 KiB | Viewed 7357 times ]
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| Fri Oct 20, 2023 7:20 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Did some board stuffing, but ran out of bypass caps and sockets.
First testing of my 4 bat alu, and it seems to work.
Attachments:
File comment: Need a real camera.
PICTESTER.JPG [ 74.02 KiB | Viewed 6726 times ]
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| Thu Oct 26, 2023 8:21 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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A 24 bit alu card
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alu24.jpg [ 54.4 KiB | Viewed 6691 times ]
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| Sat Oct 28, 2023 4:10 am |
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drogon
Joined: Sun Oct 14, 2018 5:05 pm
Posts: 62
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Can help but wonder what the old analog panel meter is doing there...
-Gordon
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| Sat Oct 28, 2023 9:32 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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I wish to have a good idea of the static power used, by the alu module so I need the meter.
With this I can size pcb power and ground tracks.
The current design emulates a core memory computer, but the exact timing is a state of flux.
The goal is about 1.4 us for a memory cycle, using a 2901 alu around 1976.
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| Sat Oct 28, 2023 1:42 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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After I sent the PCB off, I found a schematic error with a last minute change. 1 wire cut and 2 jumpers.
Attachments:
ALU-SHEET1.pdf [620.84 KiB]
Downloaded 597 times
alu.jpg [ 56.95 KiB | Viewed 4778 times ]
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| Tue Nov 21, 2023 10:49 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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The mother board. Hope to have it out the door tomorow.
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mom.png [ 179.06 KiB | Viewed 1831 times ]
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| Fri Dec 15, 2023 7:36 am |
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robfinch
Joined: Sat Feb 02, 2013 9:40 am
Posts: 2095
Location: Canada
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Are all those resistors to hold the bus?
_________________Robert Finch http://www.finitron.ca
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| Sun Dec 17, 2023 8:33 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Bus termination of 1K pulled down with 2.2K. TTL drive for the control, LS logic for the reciever. Prototype logic still.
PS: The PCB's have shipped, I am expecting Thursday,
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| Sun Dec 17, 2023 9:54 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Status from DHL,
Arrived at DHL Sort Facility EAST MIDLANDS - UK December, 21 2023
I wonder how many countries, it will visit.
Origin Service Area : SHENZHEN - CHINA MAINLAND
Destination Service Area : NORTHERN ALBERTA, AB - CANADA
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| Thu Dec 21, 2023 7:17 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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The mother board PCB is in today. Hope to have all the PCB's 4 bit alu's, alu and mother board stuffed around the start of the new year.
The first round of the Control card is done. Simple 24 bit cpu with 5 registers, A,A',X,S,PC. All one word instrctions. 64K word memory.
Attachments:
CTL.jpg [ 57.39 KiB | Viewed 1738 times ]
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| Thu Dec 28, 2023 10:22 pm |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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Added a hex display for the current state. Routing is done,just have to re-check the pal logic and pinouts.
1.08 us memory access time about 1967.
Attachments:
CTL.jpg [ 64.85 KiB | Viewed 1726 times ]
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| Sun Dec 31, 2023 4:57 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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IT's DEAD JIM !
The power on reset chip, dies when I plug In the ALU card into the mother board.
Tries a 3 pin POR chip, still stays in reset.
Waiting for some 555 timers, for reset using dead bug wireing.
The good news is the ALU card seems to work.
Attachments:
File comment: 555...554...553
t555.png [ 59.37 KiB | Viewed 1460 times ]
File comment: Counting down, for that 3 minute egg.
talu.jpg [ 867.43 KiB | Viewed 1460 times ]
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| Sat Jan 06, 2024 4:01 am |
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oldben
Joined: Mon Oct 07, 2019 2:41 am
Posts: 593
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70's tec lives. I now have 74H04's, TIL311's and NE 555 timers. My dead bug POR works.
I still have to revise the single step logic for PAL timing logic on the mother board, to use IDLE-,
right now it just holds the clock. As a side note, my Control logic PCB has just left Hong Kong.
I just need to dig out more Solder and a New Iron tip from my junk box for that.
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| Sat Jan 06, 2024 6:58 pm |
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