US Patent 8078800 Dynamic operating point modification in an integrated circuit

In one embodiment, an integrated circuit includes a processor, an internal memory, and a memory controller coupled to an external memory. The integrated circuit may support two or more modes of operation, with different operating points. To switch from one operating point to another, code executed by the processor may copy switch code from the external memory into the internal memory, and may jump to the switch code. Executing out of the internal memory, the switch code may communicate with the memory controller to cause the external memory to enter into self-refresh mode. The operating point may be altered, and the switch code may reinitialize the memory controller after the integrated circuit has stabilized at the new operating point. After the memory controller's physical interface circuit has relocked, the external memory may exit self-refresh mode.