US Patent 12137081 Resource access in a microcontroller

A microcontroller is provided and comprises a central repository, a processing device, and a firewall. Rule repository memory in the central repository stores one or more access rules defining an access permission of a software context to one or more target resources of the microcontroller. The firewall receives a bus transaction initiated based on an instruction and determines whether any access rule stored in memory of the firewall defines the access permission of the software context to a destination resource. If no access rule stored in the firewall memory defines the access permission, the firewall communicates a miss query condition to the central repository. The central repository searches the rule repository memory for an access rule defining the access permission of the software context to the destination resource, and if a related access rule is found, the related access rule is stored in the firewall memory.