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 Getting it working. 
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Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Preview of the ALU card.


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Fri Oct 20, 2023 5:07 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Now 24 bits. .750 us core cycle 1.5 us Memory cycle 1974 74xx & 74Hxx


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Fri Oct 20, 2023 7:20 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
Did some board stuffing, but ran out of bypass caps and sockets.
First testing of my 4 bat alu, and it seems to work.


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Thu Oct 26, 2023 8:21 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
A 24 bit alu card


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Sat Oct 28, 2023 4:10 am

Joined: Sun Oct 14, 2018 5:05 pm
Posts: 62
Can help but wonder what the old analog panel meter is doing there...

-Gordon


Sat Oct 28, 2023 9:32 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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.


Sat Oct 28, 2023 1:42 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
After I sent the PCB off, I found a schematic error with a last minute change. 1 wire cut and 2 jumpers.


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Tue Nov 21, 2023 10:49 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
The mother board. Hope to have it out the door tomorow.


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Fri Dec 15, 2023 7:36 am

Joined: Sat Feb 02, 2013 9:40 am
Posts: 2104
Location: Canada
Are all those resistors to hold the bus?

_________________
Robert Finch http://www.finitron.ca


Sun Dec 17, 2023 8:33 am WWW

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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,


Sun Dec 17, 2023 9:54 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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


Thu Dec 21, 2023 7:17 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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.


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Thu Dec 28, 2023 10:22 pm

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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.


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Sun Dec 31, 2023 4:57 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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.


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Sat Jan 06, 2024 4:01 am

Joined: Mon Oct 07, 2019 2:41 am
Posts: 619
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.


Sat Jan 06, 2024 6:58 pm
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