Designing an Intel 8008 Computer. Part 1: Power, Clocks and Signals
The Intel 8008 was the second microprocessor, and the first 8-bit one, as well as being the first microprocessor to go on general sale. It’s an interesting and quirky beast which was constrained by bleeding edge technology and a curious edict from the Intel management. In terms of history, the 8008 was designed under contract …. Read More
Passing Code Pointers as Data in Amstrad CPC BASIC
One of my secret coding pleasures is passing a function as a parameter to a subroutine. Most modern languages have what’s called ‘first class code’. That means that you can assign the address of a function to a variable, store it in an array, and pass it as a parameter to a function. This enables …. Read More
Comparing Datapoint 2200, 8008, 8080 and Z80 Instruction Sets
Before Intel created the 8080 it designed the 8008, the first eight bit microprocessor, and the first microprocessor to go on general sale. The 8008 was designed as a single chip version of the TTL processor in the Datapoint 2200, itself the first desktop computer. I’ve long known that the Datapoint 2200 had a very …. Read More
Variables, DEF FN Definitions and Arrays Storage in Amstrad CPC/Locomotive BASIC
(The information in this article comes from reverse engineering Amstrad CPC BASIC. You can find the reverse engineered source code in my CPC BASIC source code repository. You can find an example BASIC program which ‘walks’ the storage areas in the Examples folder of that repository. See also the CPC Wiki page for more technical …. Read More
Couch To 64k Part 4: Adding a Keypad/Keyboard to our Z80 Breadboard Computer
In the previous part of this series we added a character LCD display to our breadboard computer. We discussed how input, output and address decoding works on the Z80, which means we know most of what we need to know to be able to add an input device. In this part we’ll be adding some …. Read More
Couch to 64k – a.k.a. Building a Z80 Breadboard Computer. Part 1: Pins
A lot of people build Z80 based computers. They build something with some flashing LEDs, some buttons, and maybe even a serial port. But the computers I loved as a kid had high-resolution displays, and keyboards, and joysticks attached. And you could spend your days playing games on them. So, I’m going to attempt to …. Read More