Documentation

// NRF24L01+ PA LNA - Arduino TX
// Library: RF24 by TMRh20 (Arduino Library Manager)

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(9, 10);  // CE, CSN
const byte address[6] = "NODE1";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.setPALevel(RF24_PA_HIGH);  // for PA LNA, RF24_PA_HIGH is sweet spot
  radio.setDataRate(RF24_250KBPS);  // longest range
  radio.openWritingPipe(address);
  radio.stopListening();
}

void loop() {
  const char text[] = "Hello from PA LNA!";
  bool ok = radio.write(&text, sizeof(text));
  Serial.println(ok ? "Sent OK" : "Send failed");
  delay(1000);
}

// NRF24L01+ PA LNA - Arduino RX
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(9, 10);  // CE, CSN
const byte address[6] = "NODE1";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.setPALevel(RF24_PA_HIGH);
  radio.setDataRate(RF24_250KBPS);
  radio.openReadingPipe(0, address);
  radio.startListening();
}

void loop() {
  if (radio.available()) {
    char text[32] = "";
    radio.read(&text, sizeof(text));
    Serial.print("Got: "); Serial.println(text);
  }
}

# NRF24L01+ on Pico - MicroPython
# Use micropython-mrequests or peterhinch's nrf24l01 driver

from machine import Pin, SPI
import nrf24l01
import struct, time

spi = SPI(0, baudrate=4000000, polarity=0, phase=0,
          sck=Pin(2), mosi=Pin(3), miso=Pin(4))
nrf = nrf24l01.NRF24L01(spi, cs=Pin(5), ce=Pin(6), payload_size=8)
nrf.set_channel(76)
nrf.set_power_speed(nrf24l01.POWER_3, nrf24l01.SPEED_250K)

# TX:
nrf.open_tx_pipe(b'NODE1')
nrf.send(struct.pack('i', 1234))

# RX:
nrf.open_rx_pipe(0, b'NODE1')
nrf.start_listening()
while True:
    if nrf.any():
        data = nrf.recv()
        print('Got:', struct.unpack('i', data))
    time.sleep_ms(20)