Atmel : 2.4GHz RF MCU – SMART™ SAM R21 is ideal for use in ZigBee networks

The Atmel® | SMART™ SAM R21 is a series of low-power microcontrollers which include a 32-bit ARM® Cortex®-M0+ processor core and a low-power 2.4GHz ISM-band transceiver. The SAM R21E and SAM R21G devices may run either proprietary communication stacks or systems which comply with the IEEE 802.15.4 standard, including the ZigBee® protocol.

The SAM R21 series is available in 32- and 48-pin packages with up to 256kbytes of Flash and 32kbytes of SRAM. They operate at a maximum clock frequency of 48MHz and achieve processor throughput of 2.46 Coremark/MHz.

All devices include intelligent and flexible peripherals, the Atmel Event System technology for inter-peripheral signalling, and support for capacitive touch-button, slider and wheel user interfaces.

The MCUs’ extremely low power consumption helps to extend battery life, and makes them suitable for use in battery-less and energy-harvesting designs.

Antenna diversity helps to improve wireless connectivity and extends range. The transceiver offers a maximum data rate of 2Mbits/s.

The SAM R21 series provides one USB2.0 Full-Speed embedded host and device interface. Up to five serial communication modules can each be configured to act as a USART, UART, SPI, I2C or LIN slave.

In addition, the chip features an 8-channel, 350ksamples/s 12-bit ADC with programmable gain and optional oversampling and decimation supporting up to 16-bit resolution. It also has two analogue comparators, and a peripheral touch controller supporting up to 48 buttons, sliders and wheels as well as proximity sensing.

The SAM R21 devices are supported by a full suite of programme and system development tools, including C compilers, macro assemblers, debuggers/simulators, programmers and evaluation kits.


  • -99dBm receiver sensitivity
  • Up to +4dBm Transmit power
  • <70μA/MHz current
  • 12-channel DMA controller
  • AES 128-bit hardware encryption
  • External RF front-end control


  • Wireless networking equipment
  • IoT devices


The Atmel® SAM R21 Xplained Pro evaluation kit features an ATSAMR21G18A RF microcontroller. Supported by the Atmel Studio integrated development platform, the kit includes an on-board embedded debugger; no external tools are necessary to programme or debug the MCU.
Orderable Part Number: ATSAMR21-XPRO