Datasheet

Page 21 of 161
nRF8001 Product Specification
Revision 1.2
7 Interfaces
This chapter defines the physical interfaces for nRF8001:
• Application Controller Interface (ACI)
• Active signal
• Bluetooth low energy Direct Test Mode Interface
7.1 Application Controller Interface (ACI)
The Application Controller Interface (ACI) enables an application controller to communicate with nRF8001.
The ACI consists of a physical transport which is described in this chapter and a logical interface which is
described in Part B of this product specification.
7.1.1 Physical description
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.
These hand shake signals allow nRF8001 to notify the application controller when it has received new data
over-the-air and also to hold new data exchanges initiated by the application controller until it is ready to
accept and process them. The ACI connections are shown in Figure 7.
Figure 7. ACI interface between application controller and nRF8001
Application
controller
nRF8001
RDYN
SCK
MISO
REQN
Input
Output
Input
Output
Output
Input
Input
Output
Output
Input
MOSI