The hardware and video timing code are derived from PIC-Pong. The original concept was to try to do a video overlay clock, but the horizontal resolution isn't that great so the digits end up being too large to be useful for aan overlay, so we never actually built the overlay circuitry. The credits were thrown in as a test of the smooth scrolling that I wanted for another video game which I haven't yet written.
As with PIC-Pong, the processor is run at 18.432 MHz. The video timing doesn't meet NTSC spec: it is noninterlaced and has 256 scan lines per frame, with exactly 60.0 frames per second. It is close enough to work on normal NTSC televisons and monitors. It may not be close enough for VCRs.
The code for this project is available under the terms of the Free Software Foundation's General Public License, Version 2. If you agree to the terms of the license, you may download a copy in either tar or zip format:
Last updated September 8, 1997
Copyright 1995, 1997 Eric Smith