Figure 1 Differences in the application design range for microcontrollers and system LSIs (ASIC)
With microcontroller application systems, components other than those used for ordinary microcontrollers are operated in line with the reference clock supplied by the microcontroller. On the contrary, for an ASIC with a built-in CPU, the CPU core (a microcontroller that has been converted to IP) as well as other components must be operated based on the same clock.