Microcontroller having selectable bus timing modes based on primary and secondary clocks for controlling the exchange of data with memory

摘要

An integrated circuit microcontroller with improved system bus timing modes that allow higher speed operation when accessing external memory. The improved system bus timing modes are generated by using the edges of a higher frequency secondary clock to trigger system bus timing events instead of using the edges of the phase clock. This can be done without major redesign using combinational logic because the phase clock and the higher frequency secondary clock are substantially in-phase.