View source for Arduino Bluetooth Low Energy (BLE) Shield



==  Introduction ==








This shield is designed to work with Arduino boards, including Arduino Uno, Mega and Leonardo. 

the shield supports connection between Arduino and iOS device including iPhone 5, iPhone 4S, iPad 3rd generation and iPod touch 5th generation.


== Features ==
*SPI to Bluetooth.
*Fully qualified Bluetooth® v4.0 low energy Connectivity IC with integrated Radio, Link Layer, and Host stack
*Cost-optimized solution for Peripheral (Slave) role operation
*Best-in-class power consumption enabling months to years of battery lifetime when running from standard CR2032 coin cells
*On-chip DC/DC regulator enabling up to 20% peak current reduction for 3V cells
*Fully integrated, low tolerance 32kHz RC oscillator eliminating the need for external 32kHz crystals
*Simple serial interface (ACI) supporting a range of different external application microcontrollers



== NOTE ==
*Requires iPhone 5, iPhone 4S, iPad mini, iPad with Retina display (4th gen), iPad (3rd gen) or iPod touch (5th gen).


== Hardware ==
Nordic nRF8001 Bluetooth Low Energy IC

*Support Peripheral (Slave) role operation only - nRF8001 IC limitation.
*Proprietary simple serial interface - Application Controller Interface (ACI).
*Please refer to Nordic’s nRF8001 Product Specification for more details.

Application Controller Interface (ACI)

*The ACI enables an application controller to communicate with nRF8001.
*The physical ACI interface on nRF8001 consists of five pins. All ACI data exchanges use a standard SPI interface, with nRF8001 using a mode 0 slave interface to the application controller.
*However, nRF8001 does not behave as a pure SPI slave device; nRF8001 can receive new data over-the- air at any time or be busy processing a connection event or new data. *Consequently, the traditional CSN signal used to initiate an SPI transaction is replaced by two active low hand-shake signals; RDYN and REQN.
Signal	Arduino	nRF8001	Description
MISO	Input	Output	SPI: Master In Slave Out
MOSI	Output	Input	SPI: Master Out Slave In
SCK	        Output	Input	SPI: Serial data Clock
REQN	Output	Input	application controller to nRF8001 handshake signal
RDYN	Input	Output	nRF8001 to application controller handshake signal
  

Pins Availability

Since we have to enable SPI interface for ACI communication, some I/O pins will not be available for other usage. On Arduino Uno, the SPI bus uses pins 10 (SS), 11 (MOSI), 12 (MISO), and 13 (SCK). On the Arduino Mega, they are 50 (MISO), 51 (MOSI), 52 (SCK), and 53 (SS). For Leonardo, the SPI pins are not connected to any of the digital I/O pins as they are on the Uno and Mega, they are only available on the ICSP connector. Our BLE Shield is designed to utilize the SPI pins on the ICSP Header, therefore it is compatible with all three Arduino models.

Moreover Nordic’s ACI requires two hand-shake signals, RDYN and REQN, two additional pins will be used (pins 8 & 9 in the current implementation). 

== Use ==