NRF24L01P-R7 datasheet(75/78 Pages) NORDIC

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nRF24L01+ Product Specification

Appendix A - Enhanced ShockBurst™ - Configuration and communi-

cation example

Enhanced ShockBurst™ transmitting payload

Set the configuration bit PRIM_RX low.

When the application MCU has data to transmit, clock the address for the receiving node

(TX_ADDR) and payload data (TX_PLD) into nRF24L01+ through the SPI. The width of TX-pay-

load is counted from the number of bytes written into the TX FIFO from the MCU. TX_PLD must

be written continuously while holding CSN low. TX_ADDR does not have to be rewritten if it is

unchanged from last transmit. If the PTX device shall receive acknowledge, configure data pipe 0

to receive the ACK packet. The RX address for data pipe 0 (RX_ADDR_P0) must be equal to the

TX address (TX_ADDR) in the PTX device. For the example in Figure 14. on page 41 perform the

following address settings for the TX5 device and the RX device:

TX5 device: TX_ADDR = 0xB3B4B5B605

TX5 device: RX_ADDR_P0 = 0xB3B4B5B605

RX device: RX_ADDR_P5 = 0xB3B4B5B605

A high pulse on CE starts the transmission. The minimum pulse width on CE is 10µs.

nRF24L01+ ShockBurst™:

Radio is powered up.

16MHz internal clock is started.

RF packet is completed (see the packet description).

Data is transmitted at high speed (1Mbps or 2Mbps configured by MCU).

If auto acknowledgement is activated (ENAA_P0=1) the radio goes into RX mode immediately,

unless the NO_ACK bit is set in the received packet. If a valid packet is received in the valid

acknowledgement time window, the transmission is considered a success. The TX_DS bit in the

STATUS

not received in the specified time window, the payload is retransmitted (if auto retransmit is

enabled). If the auto retransmit counter (ARC_CNT) exceeds the programmed maximum limit

(ARC), the MAX_RT bit in the STATUS register is set high. The payload in TX FIFO is NOT

removed. The IRQ pin is active when MAX_RT or TX_DS is high. To turn off the IRQ pin, reset the

interrupt source by writing to the STATUS register (see Interrupt chapter). If no ACK packet is

received for a packet after the maximum number of retransmits, no further packets can be trans-

mitted before the MAX_RT interrupt is cleared. The packet loss counter (PLOS_CNT) is incre-

mented at each MAX_RT interrupt. That is, ARC_CNT counts the number of retransmits that were

required to get a single packet through. PLOS_CNT counts the number of packets that did not get

through after the maximum number of retransmits.

nRF24L01+ goes into standby-I mode if CE is low. Otherwise, next payload in TX FIFO is trans-

mitted. If TX FIFO is empty and CE is still high, nRF24L01+ enters standby-II mode.

If nRF24L01+ is in standby-II mode, it goes to standby-I mode immediately if CE is set low.

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