This is a small dev board for Energy Micro's EFM32G880F128 processor. The manufacturers claim 8 bit power consumption despite 32 bit performance.

FEATURES:

• MCU: EFM32G880F128 32 bit Cortex-M3™ with 128K Bytes Program Flash, 16K Bytes RAM, 85 GPIO, 8 Channel DMA, 12 bit ADC 1Msps, 3xUART/SPI, 2x low power UART, I2C, 3x 16bit TIMERS, 3x2 CC-PWM, SSC, RTC, WDT, up to 32MHz operation
• Standard JTAG connector with ARM 2x10 pin layout for programming/debugging with ARM-JTAG-EW
• UEXT connector
• Power jack
• RESET circuit
• RESET button
• Status LED
• User button
• On board voltage regulator 3.3V with up to 800mA current
• Power supply LED
• Power supply filtering capacitor
• 16 Mhz crystal
• Extension headers for all uC ports + RST and power supply
• PCB: FR-4, 1.5 mm (0,062"), soldermask, silkscreen component print
• Dimensions: 70 x 43 mm ( 2.75 x 1.7 ")
• Distance between the headers: 25.4 mm (1")

• EM-32G880F128-H.pdf - user manual

• EM-32G880F128-H schematic

• EM-32G880F128-H demo project for EW-ARM 5.41