Nordic Semiconductor nRF51 Development Kit board (PCA10028).

• Debug Interfaces
  J-Link	Micro-USB
  J-Link	Debug in: 10-pin Cortex Debug Connector
  J-Link	Debug out: 10-pin Cortex Debug Connector
  CMSIS-DAP	Micro-USB

• Core features
  Other Core Feature	1 x Bluetooth Low Energy (Bluetooth Smart) support
  Other Core Feature	1 x ANT/ANT+ support

• Debug
  Integrated Debug Adaptor	1 x On-board J-Link

• Other
  Crystal Oscillator	16 MHz Crystal Oscillator
  Crystal Oscillator	32.77 KHz Crystal Oscillator
  Other Feature	1 x mbed Enabled
  Other Feature	1 x On-board PCB antenna

• Power
  Power Supply	5 V - 0 V USB Powered
  Power Supply	1.8 V - 3.6 V External power supply
  Power Socket	1 x USB
  Power Socket	2 x Pins for an external power supply
  Power Socket	1 x CR2032 coin cell battery socket

• I/O
  Digital I/Os	31 x IOs available on extension headers with 2.54 mm pitch

• Connectors
  USB	1 x USB
  Other Connector Type	1 x Connector for current measurement
  Other Connector Type	1 x Connector for RF measurement
  Other Connector Type	1 x Virtual COM port via UART

• Display
  LEDs	4 x LEDs

• Controls
  Push-buttons	5 Push-buttons: IF BOOT/RESET, 4 x User

• Form factor
  Arduino Formfactor	Arduino Formfactor