MSC file for JTAG update with Xilinx IMPACT tool: f18a_250k_v18-mcs
In-System Update for TI-99/4A Computer: F18AUpdate_v18
A small update to fix a sprite collision bug where sprite collisions were being incorrectly detected outside of the active display, and added hybrid VDP register write restriction to mask VDP register writes […]
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” […]
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
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 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.
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 […]
When I first started the F18A project I figured getting a minimal FPGA board to run it on would be easy. After all, I bought my fully loaded devboard for about $150, and the only thing I needed was the FPGA and a few connectors.
Well, I’m here to tell you it did […]
Download: TidBit source
V3.0 – Updated on September 13, 2016
TidBit was created to help write TI-99/4A BASIC and Extended BASIC programs. TidBit is a pre-processor that lets you write your code in a more natural way (no line numbers, use indentation and comments, use labels, etc.) and then generates a normal BASIC/XB program that […]
Bank Switch Mini 256K
When I started selling the Classic 64K Bank-Switch Boards on the CHC store, I wanted to follow Jon’s lead and offer a cartridge shell. Currently the only place to get a 99/4A cartridge shell is to removed the circuit board from an existing TI produced cartridge, at least until someone […]
In August 2007 I finally decided to purchase an FPGA development board. I chose the Digilent Spartan 3E Started Board, which is actually still available for the same price I paid 3 years ago… I’m not sure if that is a good thing or a bad thing? Anway, I made my choice based on a […]