Control system

A control system, comprising:

• a power supply unit that supplies a plurality of power voltages;
• and
• a control unit connected to the power supply unit and a CPU,
• wherein said control unit includes:
• a storage section that correlatively stores power voltages and frequencies of a clock signal that a plurality of functions with which said CPU is provided need;
• a power supply control section that causes said power supply unit to supply the highest power voltage from among those power voltages corresponding to functions that operate in said plurality of functions stored in said storage section;
• and
• a clock supply section that supplies the clock signal having the highest frequency from among those frequencies corresponding to functions that operate in said plurality of functions stored in said storage section,
• wherein said power supply unit includes:
• a power supply section that supplies the power voltage specified by said power supply control section to said CPU;
• and
• an interrupt notification section that notifies said control unit that the power voltage supplied from said power supply section has changed,
• wherein if switching from one function to another function occurs in such a manner that the frequency of the clock signal supplied from said clock supply section for the latter function is lower than that for the former function, after the frequency of the clock signal for the latter function has been set up, said power supply control section causes said power supply section to supply the power voltage corresponding to the changed frequency, and
• wherein if switching from one function to another function occurs in such a manner that the frequency of the clock signal supplied from said clock supply section for the latter function is higher than that for the former function, after said notification is received from said interrupt notification section, said clock supply section supplies the clock signal having the frequency corresponding to the latter function.