F18A Firmware Update

After a year of work I’m happy to announce the release of the F18A V1.6 Firmware. There have been many changes (see below), most of which were driven by suggestions, wishes, and feedback.

The main focus of the V1.6 changes was usability. When I created many of the initial F18A features I did not have […]



For a long time I hesitated engaging the idea of writing an SDRAM controller. I think my reluctance was due to the stigma that SDRAM controllers are extremely hard and complicated, and I always wanted something quick and simple. Once I finally committed to designing one and after looking at two other more simplistic […]

F18A In-System Update

Thanks to the help of several fellow 99/4A enthusiasts (Rasmus and Tursi), I’m happy to announce an in-system software update for the F18A firmware. Currently the update program only runs on a 99/4A system and requires a bulk-storage device large enough to contain the update program, bit stream, and data file on the same “disk” […]

F18A Pinout

Anyone interested in using the F18A in their own computer or microcontroller system, please start with the TMS9918A datasheet since the electrical interface, host CPU interface, and timing specifications of the F18A are the same as the TMS9918A. I’m only going to outline the F18A differences here.

Since the F18A runs at a higher internal […]

Disconnect Between the Layers

I have been programming for a long time, and for the last few years I started working on the hardware side of things too. Something that has really come to my attention recently is how much disconnect there is between the “layers” of producer-to-user. I suppose this kind of disconnect might also exist in other […]

F18A Programming Introduction

0.0 F18A Register Use Spreadsheet

The register use spreadsheet is essential to programming the F18A and shows how all the extra VDP registers are used and what features they provide.

Download the F18A_Register_Use Spreadsheet

1.0 Introduction

Programming the F18A is very similar to the original 9918A VDP. Because the F18A is a pin-compatible replacement for […]

Mounting the F18A VGA Connector

Mounting the F18A VGA connector to your system case is *highly* recommended! The F18A is not designed to withstand any pulling on the VGA cable and requires good strain relief. One good “tug” can easily rip the F18A out of the socket and bend or break the PCB pins on the bottom of the board.


F18A Features

Test of the Bitmap Layer

Since the F18A is now shipping (finally!), and the feature list is stable (heh, yeah right…) I need to get my website updated, and eventually write some documentation so people can use the enhance features. For now I will try to make a comprehensive list of the features with […]


Update: March 19, 2012

I learned over the weekend that ceramic SMD capacitors cannot be reliably soldered using a soldering iron. It seems the ceramic material expands at a different rate than the circuit board and causes microscopic cracks in the crystalline structure of the ceramic. Apparently this will cause the parts to fail over […]

Looking For Gadget Inspiration?

Me too.

I have a huge collection of all things Arduino – LCDs, touchscreens, cases, batteries, ICs, sensors, knobs, switches, wires and everything in between. And I can’t come up with a single thing to build and USE.

I’m not an academic hacker so I like to make things I need, or at least things […]