Building an ALU From EPROM – The Circuit

When I wrote my blog post about building an ALU from an EPROM, I intended to use an EPROM from my old bag of parts.  Unfortunately, none of my old UV erasable PROMs worked with the programmer.  I’m assuming they are old and not usable.  So I purchased a pair of 28C64’s from Jameco Electronics.  … Read moreBuilding an ALU From EPROM – The Circuit

Vintage Computer Hardware Design

Summary In this blog post I’m going to talk about some computers that came out in the late 70’s and early 80’s.  These are some of the earliest home computers and utilized mostly 8-bit CPUs.  Schematics are available and I’ve done some deep-diving into the circuitry to see how these machines were created.  The first … Read moreVintage Computer Hardware Design

Legacy Code – Dealing with Classic ASP

Summary I’ve written quite a few blog posts about legacy code.  In this blog post I’m going to discuss how you can deal with classic ASP, why you should deal with it sooner than later and some details of what to do. Classic ASP If you’re running a .Net shop, Classic ASP is about the … Read moreLegacy Code – Dealing with Classic ASP

Generic Array Logic Hexadecimal Display

I’ve always wanted a decoder that did more than the TTL 7447 BCD to seven-segment display decoder did.  I wanted the full hexadecimal output.  One of my first real projects for the GAL was to create such a chip.  I have an old PAL databook that was published by National Semiconductor in 1982.  I pulled … Read moreGeneric Array Logic Hexadecimal Display

Digital Electronics for the Beginner

Let’s say you’re a programmer and your experience in digital electronics involves that one class you were required to take in college.  Or…you’re a young person who is interested in learning this cool stuff, because, well… it seems cool.  One option is to buy one of those learning kits and go through the tutorials.  If … Read moreDigital Electronics for the Beginner