PDP-8/e Replicated — A Different Implementation

Matters of cake

It has been almost a year since I got a different implementation of my PDP-8/e replica project for my birthday. Yes, it was a cake, and I have neglected to share it with the world so far. To be fair, there was a time this year where everything was a cake, at least on Twitter, and adding another one would have just been pouring gasoline on the fire. But here it is, first a side by side comparison of the implementations: [Read More]
pdp8  pdo 

Other Vintage Computer Replication Projects

A few weeks back, I was showing my PDP-8/e project at the Vintage Computer Festival in Zurich. While I was doing my project, I haven’t really checked if there were other projects like this. At least for the PDP-8 I knew there wasn’t, the only FPGA core I could find was a new implementation of the architecture that is binary compatible but doesn’t attempt to replicate the structure and instruction cycles of any specific PDP-8. [Read More]
pdp8  pdo 

GHDL Back in Debian

As I have noted, I have been working on packaging the VHDL simulator GHDL for Debian after it has dropped out of the archive for a few years. This work has been on slow burner for a while and last week I used some time at DebConf 18 to finally push this to completion and upload it. ftpmasters were also working fast, so yesterday the package got accepted and is now available from Debian unstable. [Read More]
debian  pdo 

PDP-8/e Replicated — Clocks And Logic

This is, at long last, part 3 of the overview of my PDP-8/e replica project and offers some details of the low-level implementation. I have mentioned that I build my PDP-8/e replica from the original schematics. The great thing about the PDP-8/e is that it is still built in discrete logic rather than around a microprocessor, meaning that schematics of the actual CPU logic are available instead of just programmer’s documentation. [Read More]
pdp8  pdo 

Fixing a Nintendo Game Boy Screen

do this one thing

Over the holidays my old Nintendo Game Boy (the original DMG-01 model) has resurfaced. It works, but the display had a bunch of vertical lines near the left and right border that stay blank. Apparently a common problem with these older Game Boys and the solution is to apply heat to the connector foil upper side to resolder the contacts hidden underneath. There’s lots of tutorials and videos on the subject so I won’t go into much detail here. [Read More]

Reviving GHDL in Debian

It has been a few years since Debian last had a working VHDL simulator in the archive. Its competitor Verilog has been covered by the iverilog and verilator simulator packages, but GHDL was the only option for VHDL in Debian and that has become broken, orphaned and was eventually removed. I have just submitted an ITP to make my work on it official. A lot has changed since the last Debian upload of GHDL. [Read More]
debian  pdo 

PDP-8/e Replicated — Overview

This is an overview of the hardware and internals of the PDP-8/e replica I’m building. The front panel board If you know the original or remember the picture from the first post it is clear that this is a functional replica not aiming to be as pretty as those of the other projects I mentioned. I have reordered the switches into two rows to make the board more compact (which also means cheaper) without sacrificing usability. [Read More]
pdp8  pdo 

PDP-8/e Replicated — Introduction

I am creating a replica of the DEC PDP-8/e architecture in an FPGA from schematics of the original hardware. So how did I end up with a project like this? The story begins with me wanting to have a computer with one of those front panels that have many, many lights where you can really see, in real time, what the computer is doing while it is executing code. Not because I am nostalgic for a prior experience with any of those — I was born a bit too late for that and my first computer as a kid was a Commodore 64. [Read More]
pdp8  pdo 

New Blog

So I finally got myself a blog to write about my software and hardware projects, my work in Debian and, I guess, stuff. Readers of planet.debian.org, hi! If you can see this I got the configuration right.

For the curious, I’m using a static site generator for this blog — Hugo to be specific — like all the cool kids do these days.