Fig. 1. Memory addresses of bytes mapped onto TV screen in sample program.

to work in conjunction with the new graphics IC. This allows you to display any 256-byte segment of memory on a CRT monitor or TV receiver. The output of the new chip is a 1-volt composite video/sync signal.

The selected segment of memory appears on-screen as an array of small squares that represent individual memory bits. If a memory bit is a 1, the appropriate square will be white, while if a bit is a 0, the square will be dark. Changing the bit pattern within the memory will change the pattern that appears on-screen. You can store several different bit patterns (pictures) in memory and, [43]