8 bit computer, ALU complete

Everything is connected now on the ALU board.

  • the bus has been connected (blue wires)
  • the A register is connected to the ALU chips (purple wires)
  • the B register is connected  to the ALU chips (green wires)
  • the ALU output is connected to the connector (grey wires)
  • the output of the B register is connected to the top connector (coloured flatcable)

First ALU test

The ALU has undergone it’s first limited test (one addition and one subtraction). The A register contained b’00000100′, which is decimal 4 and the B register contained b’00010100′, which is decimal 20.

The addition A plus B yielded b’00011000′ (decimal 24) and the subtraction A minus B gave us b’11101111′ (decimal -16 when in 2’s complement).

Yeah! So far so good.

 

ALU is complete

SaveSave

SaveSave

SaveSave

SaveSave

SaveSave

8 bit computer, ALU complete