Preview of the ALU card.

Now 24 bits. .750 us core cycle 1.5 us Memory cycle 1974 74xx & 74Hxx

Did some board stuffing, but ran out of bypass caps and sockets.
First testing of my 4 bat alu, and it seems to work.

A 24 bit alu card

Can help but wonder what the old analog panel meter is doing there...

-Gordon

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.

After I sent the PCB off, I found a schematic error with a last minute change. 1 wire cut and 2 jumpers.

The mother board. Hope to have it out the door tomorow.

Are all those resistors to hold the bus?

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,

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

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.

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.

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.

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.