We’ll admit it, we’re all spoiled. A few bucks can now buy a computer that would have been the envy of everyone back in the late 1970s or early 1980s. So it’s no surprise that [krallja] was able to use an old-style video output chip to drive a TV with an Arduino. The TMS9918A is a venerable output device, and if the old computers could drive it then it makes sense that a modern computer could too. You can see a video of the whole experiment, below.
The Internet has also spoiled us, in that it’s dead simple to find datasheets for nearly anything, even these old chips. The only real problem with such aged silicon is that they typically expect a processor with a data and address bus, but most microcontrollers now keep all of that internal. But with enough fast I/O you can simulate a bus just fine. For now, the experiment just cycles through the color output.
The circuit on a breadboard worked fine, even if it looked like it wouldn’t survive much transportation. The next step, which we expect will be in the next video is, of course, to write data to the video RAM so actual text will appear on the screen.
One of our favorite projects from the past did the opposite: it uses an Arduino as many devices on a Z80’s address and data bus. We’ve also seen this same TI chip used in a graphics board for the RC2014 computers.