Microprocessor apparatus for secure on-die real-time clock

摘要

An apparatus including a microprocessor and an external crystal. The microprocessor executes non-secure application programs and a secure application program, where the secure application program comprises instructions from a host architecture instruction set, and where the non-secure application programs are accessed from a system memory via a system bus and the secure application program is accessed from a secure non-volatile memory via a private bus coupled to the microprocessor. The microprocessor has a secure real time clock that provides a persistent time, where the secure real time clock is only visible and accessible by the secure application program when the microprocessor is executing in a secure mode. The external crystal is coupled to the secure real time clock within the microprocessor and is configured to cause an oscillator within the secure real time clock to generate an oscillating output voltage that is proportional to the frequency of the external crystal.