The STMicroelectronics Microcontroller is a ultra-low-power microcontroller incorporating the high-performance Arm® Cortex®-M0+ 32-bit RISC core operating at 32 MHz, high-speed embedded memories (32 Kbytes of Flash program memory, 256 bytes of data EEPROM and 8 Kbytes of RAM) plus an extensive range of enhanced I/Os and peripherals. It provides high power efficiency over a wide performance range.

1.8 V to 3.6 V power supply
40 to 85 °C temperature range
0.23 μA Standby mode 2 wakeup pins
0.35 μA Stop mode 16 wakeup lines
Ultra-low-power BOR brownout reset with 5 selectable thresholds
Ultra-low-power POR/PDR
0 to 32 MHz external clock
USART, SPI supported
38 fast I/Os 31 I/Os 5-Volt tolerant
32-Kbyte Flash memory
8-Kbyte RAM
256 bytes of data EEPROM
20-byte backup register
Sector protection against R/W operation