SAMD21

The SAMD21 is a family of microcontrollers from Microchip Technology (formerly Atmel) based on the 32-bit ARM Cortex-M0+ core. It is designed for low-power, cost-sensitive embedded applications and is part of the SAM D21 series.

The processor runs at up to 48 MHz and combines general-purpose processing with a range of on-chip peripherals. Memory configurations vary by device, with Flash in the tens to hundreds of kilobytes and SRAM in the low to mid tens of kilobytes, depending on the specific variant.

Peripherals include multiple serial communication modules (SERCOMs) that can be configured as UART, SPI, or I2C, a USB device controller on many variants, a 12-bit analog-to-digital converter, and various timers and analog components. The device also features an event system and a flexible clock and power management architecture that supports multiple sleep modes for low-energy operation.

Packages and I/O support a broad set of interfaces, making the SAMD21 suitable for sensor nodes, wearables, and hobbyist projects. It is commonly used in educational boards such as the Arduino Zero and in various Microchip and third-party development boards.

Development and tooling: the SAMD21 line is supported by Microchip’s MPLAB X IDE and Atmel START, as well as community-based boards and IDEs such as the Arduino core for SAMD21. The family emphasizes low power consumption and ease of use for mid-range embedded projects.