32-bit MCU has many features, including USB

The SAM D21 (ATSAMD21) low-power microcontroller uses a 32-bit Cortex-M0+ core with 64 to 256 Kbytes of flash and 8 to 32 Kbytes of SRAM. It operates from a 1.62 to 3.63 V supply over -40° to 85°C and includes a 12-bit, 350 ks/s A/D converter, a 10-bit D/A converter, two analog comparators, and a Peripheral Touch Controller.

The MCU has a full-speed USB port, DMA, I² S, up to 5 timer/counters, 16 external interrupts, and a 12-channel Event System. It takes as low as 70 uA/MHz in active mode, comes in 32, 48, or 64 pin TQFP and QFN packages, operates at up to 48 MHz, and reaches 2.14 Coremarks/MHz.