• Memory addressing and R/W works

    Paul Kocyla • 04/25/2016 at 17:58 • 0 comments

    The memory addressing and read/write operations work after having finished the wiring.
    You can select a 5-bit address by clocking +24V or GND to the 5 address relays to set or reset them.
    The memory multiplexer selects the one of the 32 cells and puts its state to the ALU-Multiplexer which can store the bit into the ALU a,b,c cells.
    A +24/GND clock on the write wire will write 1/0 to the cell.

    Video will come.

  • Wired the memory

    Paul Kocyla • 04/07/2016 at 21:11 • 1 comment

    Row 3 and 4 are the memory demultiplexer and the memory itself.
    To save wires and relays, I use resistors to latch the relays. The advantage of it is that clocking +24V will latch a bit ON and clocking the GROUND will latch it OFF.
    A relay can still hold the on-position with less than half of the nominal coil voltage, so this hack is very useful.

    I´ll modify my actual design to this kind of latching also for the address- and ALU-multiplexers. It will make the computer more powerful with a minimal amount of effort.

  • ALU wired

    Paul Kocyla • 03/20/2016 at 13:43 • 0 comments

    Finished wiring the ALU.

    The seven Relays from left to right:

    1) Reset I/O Multiplexer

    2,3) Multiplexer (latching, read mem to A, B or Carry, write sum or carry to mem)

    4) Reset ALU input A,B,Carry

    5,6,7) Input A, B, Carry (latching)

  • Build started

    Paul Kocyla • 03/18/2016 at 20:39 • 0 comments

    Placed the relays for the command demultiplexer and ALU - preparing for wiring.

    I was lucky to get the nice 4poles industrial relays for cheap on Ebay. They are used, but in good condition.