Atmel AVR Used for Generating Video

The project has the purpose of generating non-interlaced, black and white sync and image content using the Atmel AVR MCUs since they are fast enough for this application.

An NTSC-rate, non-interlaced video signal is implemented by the software used in this project. GCC and Assembler covers entirely the current version of the code which has several versions with horizontal and vertical resolution. The screen color can be read and be able draw lines, points, and text using some utilities. To obtain good pixel density, the raster generation code needs to run fast. There is some extra time to do computations, interact with users, or update state once the TV gets to the bottom line displayed.

The three video levels are generated using two bits of a port as the Mega644 connects to the TV. By dumping several bytes to the video DAC as fast as possible, a single line of the raster is drawn on active video lines. The bitmaps for the large and small characters are contained in the two big tables in flash memory. The main function of the program is to initialize timers and draws constant lines and strings.