Sharing non-sharable devices between an embedded controller and a processor in a computer system

Abstract

System and method for sharing a device, e.g., non-volatile memory, between a host processor and a microcontroller. In response to system state change to a first state wherein the microcontroller is assured safe access to the non-volatile memory (e.g., in response to power-on reset, system reset, sleep state, etc.), the microcontroller holds the system in the first state (e.g., system reset), and switches access to the non-volatile memory from the processor to the microcontroller. While the system is held in the first state, the microcontroller accesses the device (e.g., non-volatile memory), e.g., fetches program instructions/data from the non-volatile memory and loads the program instructions/data into a memory of the microcontroller. After the access, the microcontroller changes or allows change of the system state, e.g., switches access to the device, e.g., the non-volatile memory, from the microcontroller to the processor, and releases the system from the first state.