User Manual

Revision 1.0 Page 27 of 78
nRF24L01+ Product Specification
7 Enhanced ShockBurst™
Enhanced ShockBurst™ is a packet based data link layer that features automatic packet assembly and
timing, automatic acknowledgement and retransmissions of packets. Enhanced ShockBurst™ enables the
implementation of ultra low power and high performance communication with low cost host microcon-
trollers. The Enhanced ShockBurst™ features enable significant improvements of power efficiency for bi-
directional and uni-directional systems, without adding complexity on the host controller side.
7.1 Features
The main features of Enhanced ShockBurst™ are:
• 1 to 32 bytes dynamic payload length
• Automatic packet handling
• Automatic packet transaction handling
X Auto Acknowledgement with payload
X Auto retransmit
• 6 data pipe MultiCeiver™ for 1:6 star networks
7.2 Enhanced ShockBurst™ overview
Enhanced ShockBurst™ uses ShockBurst™ for automatic packet handling and timing. During transmit,
ShockBurst™ assembles the packet and clocks the bits in the data packet for transmission. During
receive, ShockBurst™ constantly searches for a valid address in the demodulated signal. When Shock-
Burst™ finds a valid address, it processes the rest of the packet and validates it by CRC. If the packet is
valid the payload is moved into a vacant slot in the RX FIFOs. All high speed bit handling and timing is con-
trolled by ShockBurst™.
Enhanced ShockBurst™ features automatic packet transaction handling for the easy implementation of a
reliable bi-directional data link. An Enhanced ShockBurst™ packet transaction is a packet exchange
between two transceivers, with one transceiver acting as the Primary Receiver (PRX) and the other trans-
ceiver acting as the Primary Transmitter (PTX). An Enhanced ShockBurst™ packet transaction is always
initiated by a packet transmission from the PTX, the transaction is complete when the PTX has received an
acknowledgment packet (ACK packet) from the PRX. The PRX can attach user data to the ACK packet
enabling a bi-directional data link.
The automatic packet transaction handling works as follows:
1. You begin the transaction by transmitting a data packet from the PTX to the PRX. Enhanced
ShockBurst™ automatically sets the PTX in receive mode to wait for the ACK packet.
2. If the packet is received by the PRX, Enhanced ShockBurst™ automatically assembles and
transmits an acknowledgment packet (ACK packet) to the PTX before returning to receive mode.
3. If the PTX does not receive the ACK packet immediately, Enhanced ShockBurst™ automatically
retransmits the original data packet after a programmable delay and sets the PTX in receive
mode to wait for the ACK packet.
In Enhanced ShockBurst™ it is possible to configure parameters such as the maximum number of retrans-
mits and the delay from one transmission to the next retransmission. All automatic handling is done without
the involvement of the MCU.