The registers content display, along with its control board, which also serves as control interface for the whole register file, is done.

The display contains 160 LEDs, which show what is contained inside of each of 8 General Purpose Registers, along with indications of which of them is going to be loaded from bus, which is enabled to bus, and which one serves as Src1 or Src2 inputs for the main ALU.

Color arrangement of the display:

Display is made from 3mm thick white plastic, to the same dimensions as all the PCBs, so it can be stacked on top of other boards. I drilled holes in it so the LEDs are nicely fitted. Since I did it by hand, it shows in somewhat uneven spacing, but overall I am satisfied with its look.

This part contains only 6 ICs, but there are a lot of connections:

Here is the other side:

And here the whole Register File stack, as seen from the side (there are some ribbon cables missing though):

---------------------------------------------------

Next I want to make the Instruction Translation board for the ALU, and Provisional Decoder board: with these, and my 16-word ROM I will be able to integrate all the parts made to date into functional, albeit very limited, Harward-architecture type computer. It will have only 16 words for instructions, and only 8 words of volatile memory (actually, the Register File, just completed).

This computer would be called "ECM-16/TTL Pilot", as this will be the first integrated test of the system, which will be capable to perform automated sequence of operations.

Next, the addressing circuitry, which will be almost as complex as the whole Pilot, with proper Instruction Decode, Memory, Storage and Interface parts will be built, so the proper computer system is to be achieved.