ocr: THE 8564 VIDEO INTERFACE CHIP (Continued) System Clock Control The new VIC chip generates several clocks used by the C128 system. The main clock is the 1 MHz clock, which operates at approximately 1 MHz at all times. Most bus operations and all I/0 operations take place in reference to this clock. The next clock to consider is the 2 MHz clock. This clock clocks selected system components, such as the processor, at 2 MHz when in 2 MHz mode. The VIC chip monitors the IOACC input, which indicates the access of an I/0 chip, and when asserted, will stretch the 2 MHz clock to synchronize all 2 MHz p ...
