STM32 Nucleo-64 boards provide an affordable and flexible way for users to test new concepts and build prototypes with STM32 microcontrollers, choosing from various combinations of performance, power consumption and connectivity. 
Arduino Uno V3 connectivity support enables easy expansion of the functionality of the STM32 Nucleo open development platform with a wide selection of specialized shields.
The STM32 Nucleo-64 board does not require any separate probe as it integrates the ST-LINK / V2-1 debugger and programmer.
The STM32 Nucleo-64 board comes with the STM32 comprehensive software HAL library along with several examples of packaged software, as well as direct access to Arm Mbed's online resources in http://mbed.org.
Characteristics
ARM Cortex-M4 32-bit Microcontroller Ref: STM32F411RET6
Frequency 100 MHz max CPU
1.7 V to 3.6 V VDD
512 KB Flash
128 KB SRAM
GPIO (50) with external interruptibility
12-bit ADC with 16 channels
RTC
Timers (8)
I2C (3)
USART (3)
SPI (5)
USB OTG Full Speed
SDIO