Transistor computer

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This is a very long term project to try to build a computer out of transistors.

The method chosen will be to have each individual module do as much of the work as possible to keep the control module as simple as possible.

For instance, the most efficient ALU would have inputs for individual selects, carry gating and control ect, and have the control module supply these signals, however I have chosen to provide a simple Operation select (3 bits), Carry in, Carry out and Zero out, with the details of the gating and selection of these signals performed by an extra board on the ALU dedicated to this purpose.

Doing it this way outsources the complexity to the ALU rather than to the Control unit and any microprogramming that may be required. However, it does mean its a lot easier to test as a unit.


Module Status
Arithmatic and Logic Unit (ALU) Nearly done. All modules complete. Needs backplane finishing.
Instruction register
Control logic
Clock logic
ALU A latch
Flag register
Register display Complete
processor RAM
Program counter High byte
Program counter Low byte
Address latch High byte
Address latch Low byte


Arithmatic and Logic Unit (ALU)Instruction registerControl logicClock logicALU A latchFlag registerRegistersRegister displayProcessor RAMProgram counter High byteProgram counter Low byteAddress latch High byteAddress latch Low bytecomputer diagram
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