framework-arduinoteensy-cxx20/libraries/RadioHead/examples/nrf51/nrf51_server/nrf51_server.pde

// nrf51_server.pde
// -*- mode: C++ -*-
// Example sketch showing how to create a simple messageing server
// with the RH_NRF51 class. RH_NRF51 class does not provide for addressing or
// reliability, so you should only use RH_NRF51 if you do not need the higher
// level messaging abilities.
// It is designed to work with the other example nrf51_client
// Tested on RedBearLabs nRF51822 and BLE Nano kit, built with Arduino 1.6.4.
// See http://redbearlab.com/getting-started-nrf51822/
// for how to set up your Arduino build environment

#include <RH_NRF51.h>

// Singleton instance of the radio driver
RH_NRF51 nrf51;

void setup() 
{
  delay(1000); // Wait for serial port etc to be ready
  Serial.begin(9600);
  while (!Serial) 
    ; // wait for serial port to connect. Needed for Leonardo only
  if (!nrf51.init())
    Serial.println("init failed");
  // Defaults after init are 2.402 GHz (channel 2), 2Mbps, 0dBm
  if (!nrf51.setChannel(1))
    Serial.println("setChannel failed");
  if (!nrf51.setRF(RH_NRF51::DataRate2Mbps, RH_NRF51::TransmitPower0dBm))
    Serial.println("setRF failed");    
}

void loop()
{
  if (nrf51.available())
  {
    // Should be a message for us now   
    uint8_t buf[RH_NRF51_MAX_MESSAGE_LEN];
    uint8_t len = sizeof(buf);
    if (nrf51.recv(buf, &len))
    {
//      NRF51::printBuffer("request: ", buf, len);
      Serial.print("got request: ");
      Serial.println((char*)buf);
      
      // Send a reply
      uint8_t data[] = "And hello back to you";
      nrf51.send(data, sizeof(data));
      nrf51.waitPacketSent();
      Serial.println("Sent a reply");
    }
    else
    {
      Serial.println("recv failed");
    }
  }
}