See all articles from QZX v10 n11
The dot patterns for the displayable characters are held in a table in ROM, in locations 1E00 to 1FFF hex. The patterns are stored in order of the character CODE, 8 bytes being used for each character, corresponding to the 8 TV scan lines used to build up each character on the TV screen. The ROM table holds the dot patterns for 64 characters, the other 64 are the inverse (white on black) versions and are produced by the SCL chip inverting the video signal.