ocr: PIN FUNCTIONS ADORESS BUS pins 1 thru 3 and 36 thru 48 The 16 bit address bus is bidirectional. As an input, the microprccessor can access any of the 34 TED control registers. In the output mode TED uses the addresses to fetch Video Matrix Pcinters, Attribute Fointers or character cell information. For microprocessor interface TED resices in locations FFOG-FF3F in memory. DATA BUS pins 25 thru 36 The 8 bit data bus is also bidirectional. The data bus activity can be separated into 2 categories: microprocessor interface ard video data interface during the above mentioned fetches. KEYBCARD LATCH ...
