05 Dec 2013 - 3 min read
ALU Construction: LED Header Pins
So far, in the construction of the three ALU cards (Logic, Arithmetic and Control) I’ve soldered down the connectors and LEDs. It’s now time to solder in some …
03 Dec 2013 - 4 min read
Backplane Design and Construction
Originally when I was thinking about how I’d connect up the various cards of this computer I had ribbon cables in mind. Ribbon cables are straightforward to use and …
02 Dec 2013 - 4 min read
ALU Construction: Connectors and LEDs
As promised in my last post it’s finally time to get the soldering iron out and make a start on constructing the three cards that make up the ALU. I’m going start …
01 Dec 2013 - 4 min read
In the last three posts I introduced the design for the 3-to-8 Function Decoder, Zero Detect circuit and the Condition Registers. In this post I’ll put all three of …
30 Nov 2013 - 4 min read
ALU Design: Condition Registers
This post covers the design of the ALU Condition Registers which along with the 3-to-8 Function Decoder and Zero Detect circuit (both covered in my previous posts) make up the …
23 Nov 2013 - 2 min read
This post covers the design of the Zero Detect circuit which along with the 3-to-8 Function Decoder (covered in my last post) and the Condition Registers (next post) make up …
20 Nov 2013 - 2 min read
This post covers the design of a 3-to-8 Function Decoder which along with the Zero Detect circuit and Condition Registers will all go in to the ALU Control Card. The Decoder …
17 Nov 2013 - 5 min read
ALU Design: 8-bit Arithmetic Unit
In the last post I introduced the design for the 1-bit Arithmetic Unit. This post covers connecting eight of these units together to make an 8-bit Arithmetic Unit along with …
15 Nov 2013 - 3 min read
ALU Design: 1-bit Arithmetic Unit
This post covers the design of a 1-bit Arithmetic Unit that can add two input bits together (B and C) with carry in and out. Here’s a schematic of the 1-bit Arithmetic …
13 Nov 2013 - 5 min read
In the last post I introduced the design for a 1-bit Logic Unit. This post covers the design effort to cram 8 of these on to a single pad board complete with connectors, …
11 Nov 2013 - 5 min read
This post covers the design of a 1-bit Logic Unit that can produce AND, OR, XOR, NOT and SHL (Shift Left) outputs from two input bits B and C. Here’s a schematic of the …
10 Nov 2013 - 6 min read
If there’s one thing a relay computer needs a lot of it’s … erm … relays (of course) … which happens to be a bit unfortunate as relays, …