Reducing energy consumption in microcontroller-based platforms with low design margin co-processors

Advanced energy minimization techniques (i.e. DVFS, Thermal Management, etc) and their high-level HW/SW requirements are well established in high-throughput multi-core systems. These techniques would have an intolerable overhead in low-cost, performance-constrained microcontroller units (MCU's). These devices can further reduce power by operating at a lower voltage, at the cost of increased sensitivity to PVT variation and increased design margins. In this paper, we propose an runtime environment for next-generation dual-core MCU platforms. These platforms complement a single-core with a low area overhead, reduced design margin shadow-processor. The runtime decreases the overall energy consumption by exploiting design corner heterogeneity between the two cores, rather than increasing the throughput. This allows the platform's power envelope to be dynamically adjusted to application-specific requirements. Our simulations show that, depending on the ratio of core to platform energy, total energy savings can be up to 20%.