Adafruit 2746 Bluefruit LE Shield makes it easy to add BLUETOOTH® Low Energy (BLE) connectivity to any Arduino-based design. The Bluefruit LE Shield connects to the Arduino or a compatible microcontroller board using the hardware SPI-interface (MISO, MOSI, SCK) plus a chip select-line, interrupt-line, and reset. The Bluefruit acts as a data pipe that can transparently transmit back and forth from the iOS or Android device. The Bluefruit LE Shield features Arm® Cortex® M0 core running at 16MHz, with 256KB Flash memory, 32KB SRAM, and an easy AT command set.
ARM Cortex M0 core running at 16MHz
256KB flash memory
Transport SPI at 4MHz with HW IRQ (5 pins required)