Close

Video display experiment (Logisim)

A project log for DM-02 8-bit Computer

The DM-02 is an 8-bit computer built (almost) entirely out of 7400-series (TTL) logic chips.

Ruud van FalierRuud van Falier 05/03/2020 at 12:520 Comments

Added an LCD to the Logisim circuit and wrote a program that outputs a 64x64 black and white bitmap image on it. 
Although the LCD has a 128x128 resolution and supports 16 bits colors, filling the entire screen would be painfully slow and color was ditched as well for that reason.

It was a good chance to test some more of the assembler and got a few bugs squashed in the process.
It also allowed me to test the general idea I had for a simple video card, which now looks very do-able.

I also received the first couple of PCB so the actual machine will now slowly start to be built.

The computer will consist of several stacked modules that are interconnected by pin socket with long pins, as such:

Not sure how many modules I'll end up with yet. The only one designed so far are the debugger (which is not more than a few sockets that hold an Arduino Mega that is connected to all the interconnected pin sockets) and the power & clock circuit that I still need to assemble. The bottom plate is empty and only meant as, well, bottom..

I'll try to publish some more updates as they happen in the coming time.

Discussions