User Manual

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nRF24L01+ Product Specification
7.8 Enhanced ShockBurst™ transaction diagram
This section describes several scenarios for the Enhanced ShockBurst™ automatic transaction handling.
The call outs in this section’s figures indicate the IRQs and other events. For MCU activity the event may
be placed at a different timeframe.
Note: The figures in this section indicate the earliest possible download (DL) of the packet to the
MCU and the latest possible upload (UL) of payload to the transmitter.
7.8.1 Single transaction with ACK packet and interrupts
In Figure 18. the basic auto acknowledgement is shown. After the packet is transmitted by the PTX and
received by the PRX the ACK packet is transmitted from the PRX to the PTX. The
RX_DR IRQ is asserted
after the packet is received by the PRX, whereas the
TX_DS IRQ is asserted when the packet is acknowl-
edged and the ACK packet is received by the PTX.
Figure 18. TX/RX cycles with ACK and the according interrupts
1 Radio Turn Around Delay
TX:PID=1 RX
PTX
PRX
RX ACK:PID=1
UL
MCU PTX
130us
1
IRQ
DL
MCU PRX
Packet received
IRQ: RX DR (PID=1)
Ack received
IRQ:TX DS (PID=1)