Datasheet

PRELIMINARY PRODUCT SPECIFICATION
nRF24L01 Single Chip 2.4 GHz Radio Transceiver
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.2 Page 17 of 39 March 2006
The length of the CRC is configurable through the SPI interface. It is important to
notice that the CRC is calculated over the whole packet including address, PID and
payload. No packet is accepted as correct if the CRC fails. This is an extra
requirement for packet acceptance that is not illustrated in the figure above.
Stationary Disturbance Detection – CD
Carrier Detect (CD) is set high when an in-band RF signal is detected in RX mode,
otherwise CD is low. The internal CD signal is filtered before presented to CD
register. The internal CD signal must be high for at least 128µs.
In Enhanced ShockBurst™ it is recommended to use the Carrier Detect functionality
only when the PTX device does not succeed to get packets through, as indicated by
the MAX_RT interrupt for single packets and by the packet loss counter
(PLOS_CNT) if several packets are lost. If the PLOS_CNT in the PTX device
indicates to high rate of packet losses, the device can be configured to a PRX device
for a short time (T
stbt2a
+ CD-filter delay = 130µs+128µs = 258µs) to check CD. If CD
was high (jam situation), the frequency channel should be changed. If CD was low
(out of range), it may continue on the same frequency channel, but perform other
adjustments. (A dummy write to the RF_CH will clear the PLOS_CNT.)
Data Pipes
nRF24L01 configured as PRX can receive data addressed to 6 different data pipes in
one physical frequency channel. Each data pipe has its own unique address and can be
configured to have individual behavior.
The data pipes are enabled with the bits in the EN_RXADDR register. By default
only data pipe 0 and 1 are enabled.
The address for each data pipe is configured in the RX_ADDR_Px registers. Always
ensure that none of the data pipes have the exact same address.
Data pipe 0 has a unique 40 bit configurable address. Data pipes 1-5 share the 32 most
significant address bits and have only the LSByte unique for each data pipe. Figure 7
shows an example of how data pipes 0-5 are addressed. All pipes can have up to 40
bit address, but for pipe 1-5 only the LSByte is different, and the LSByte must be
unique for all pipes.