This document discusses various Cortex-M series processors including the Cortex-M0, Cortex-M0+, Cortex-M3, and Cortex-M4. It describes their architecture, configuration options, and debug features. The Cortex-M0 is a 32-bit processor with optional debug and a 12-25K gate count. The Cortex-M0+ offers improvements like a 2-stage pipeline and optional MPU. The Cortex-M3 and M4 have additional options like an MPU and ETM. Debugging support includes breakpoints, watchpoints, and optional trace modules.