Datasheet

Page 22 of 161
nRF8001 Product Specification
Revision 1.2
The data exchanges on the ACI interface are split into two types:
• Commands – Exchanges that are initiated by the application controller, including data that is sent
from the application controller to nRF8001.
• Events – Exchanges that are initiated by nRF8001, including data that is sent from nRF8001 to the
application controller.
If nRF8001 has event data ready for the application controller when the processor requests a command
exchange, the command and event will be combined in a full duplex exchange. nRF8001 sends out the
event data at the same time as it receives command data. To accommodate this, the application controller
must always monitor the incoming data when issuing a command.
7.1.2 SPI mode
The ACI transport layer uses the SPI in the following mode (SPI mode 0):
Table 2. SPI signal description
Figure 8. SPI mode 0 description
7.1.3 ACI connections
The required I/O pins needed on the application controller and nRF8001 for the ACI interface are listed in
Table 3.
Table 3. ACI I/O signals for an application controller and nRF8001
Type Value
Data order Least significant bit first
Clock polarity Zero (base value for the clock is zero)
Clock phase Zero (data is read on the clock’s rising edge)
Signal
Application
controller
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
REQN (CSN)
SCK
Sample points
MOSI
MISO
0231 4567Bit # (data order)