The “SlimPro” Trusted Management Module used in AppliedMicro’s PowerPC-based PacketPro embedded processor for networking applications uses an ARM Cortex-M3 processor that boots from on-chip ROM. The approach provides tamper-proof boot code that can then load additional boot and OC code from off chip, authenticate that code, and then install it where the PowerPC processor can execute it. The ARM Cortex-M3 processor runs at 250MHz while the PowerPC application processor runs at 1GHz. (Read more from Joseph Byrne’s Microprocessor Report article here.)
This use of a smaller processor core to provide additional services (security in this case) to a larger CPU or CPU complex is an idea with legs. In fact, it’s already a rampant design approach for everything from audio and video subsystems to networking and security. It’s the premise of Semico analyst Rich Wawrzyniak’s concept of IP subsystems. It is the present and the future of SoC Realization.