Model 74181: Complete!

A project log for Homebrew Machine 2

An 8 bit breadboard computer based on the Malvino SAP-2.

Brandon ReinhartBrandon Reinhart 07/27/2019 at 18:592 Comments

Yesterday I finished wiring up and debugging the 74181. The wiring of the second half is fairly disorganized, mostly because I wanted to try to fit everything on two more boards. It was also difficult to organize the logic by function, so the ICs are unlabeled. It's mostly AND gates, with a few OR, XOR, and inverters thrown in.

Here it is pictured next to an actual 74HC181:

Since this is a 4-bit ALU, if I wanted to use this logic in the computer project I'd need to build 2! That would make the ALU nearly as complicated as my first 8-bit computer in its entirety.

Now that I've built this model of the 74181, it'll probably go on a shelf and I'll use the actual 74HC181 IC in the computer project. I'm considering this sub-project a success and I'll assemble the ALU for the new computer next.


Brandon Reinhart wrote 07/27/2019 at 20:49 point


  Are you sure? yes | no

Dave's Dev Lab wrote 07/27/2019 at 20:06 point

awesome job!

  Are you sure? yes | no