A project log for 8 Bit Breadboard CPU

A home-brew 8 bit Microprocessor built on a breadboard 64K Address Space, IRQ, and DMA 16 Bit Stack Pointer, 4 8 bit Registers or 2 16 bit

2-Zons2-Zons 01/14/2019 at 02:361 Comment

ALU is mostly complete and working.  Using 2 x LS181's.  Top right LED's show contents of input register tied to input B on 181's.  Databus (Dipswitches) tied to input A.  Blue LED is  carry not.  Bottom Right LED's show contents of output register.  Showing A XOR B.  All loopy wires are temporary for testing, as well as the 5 dipswitches on the board, they will be control signals when hooked up to the bus.  Only need to implement zero, negative, and equal flags.  I hope I can use the A=B output on the 181's and'ed but when I tested it in logisim it didn't work properly.  I haven't tested on this setup yet.


Dave's Dev Lab wrote 01/14/2019 at 05:13 point

nice work!

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