The ARM® Cortex®-M0+ processor is the most energy efficient ARM processor available. It builds on the very successful Cortex-M0 processor, retaining full instruction set and tool compatibility, while further reducing energy consumption and increasing performance. Along with the Cortex-M0 processor, the exceptionally small silicon area, low power and minimal code footprint of these processors enable developers to achieve 32-bit performance at an 8-bit price point, bypassing the step to 16-bit devices. The Cortex-M0+ processor comes with a wide selection of options to provide flexible development.
Check out our partner Jeelabs’ projects with a minimalist circuit: http://jeelabs.org/book/1450d/