Abstract: A system and method are provided for using feedback to control processor frequencies in a system-on-chip (SoC). The method is associated with an SoC having a processor operating frequency responsive to a processor supply voltage on a first SOC interface, and a controller for managing the operating frequency. The controller accepts a frequency selection command associated with a first operating frequency, at a second SoC interface. The controller sends a first voltage command associated with the first frequency, via a third SOC interface, to a voltage regulator supplying the processor supply voltage. Then, the controller monitors the processor supply voltage. In response to detecting a processor first supply voltage, the processor is enabled to operate at the first frequency.