The Cortex-M series is a family of microcontroller cores designed by ARM for embedded systems. These cores are optimized for low power consumption and high efficiency, making them ideal for applications like IoT devices, wearables, and automotive systems. They support a range of features, including a simple programming model and a rich set of peripherals. Cortex-M cores come in various versions, such as Cortex-M0, Cortex-M3, and Cortex-M4, each offering different performance levels and capabilities. They are widely used in the industry due to their scalability and compatibility with the ARM ecosystem, allowing developers to create efficient and cost-effective solutions.