SDRAM Read Cycle

FPGA VHDL SDRAM Controller

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Introduction 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 [...]
Step 1

F18A In-System Update

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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, [...]

F18A Pinout

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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 [...]

Disconnect Between the Layers

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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 [...]
Code

F18A Programming Introduction

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1.0 Introduction Programming the F18A is very similar to the original 9918A VDP.  Because the F18A is a pin-compatible replacement for the 9918A, the host system interface and all of the 9918A core functionality is identical.  If you already know how to program the 9918A, then using the enhanced [...]
F18A in the TI-99/4A

Mounting the F18A VGA Connector

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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. Even [...]
Test of the Bitmap Layer

F18A Features

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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 a brief explanation. I [...]
F18A Board

F18A PRE-ORDERS Open!

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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 [...]

Looking For Gadget Inspiration?

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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 I [...]
toobin01

Toobin’ Arcade Game

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I recently restored a Toobin’ arcade coin-operated (coinop) video game.  Operators have a habit of doing some of the most awful things to games, so I had to undo some damage and stupid modifications, like changing the marquee lighting BACK to florescent from incandescent (which seems to be a [...]
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