Optimized High Speed NRF24L01+ Driver Class Documenation  V1.0
TMRh20 2014 - Optimized Fork of NRF24L01+ Driver
pingpair_dyn.ino

This is an example of how to use payloads of a varying (dynamic) size on Arduino.

/*
Copyright (C) 2011 J. Coliz <maniacbug@ymail.com>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.
*/
#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
//
// Hardware configuration
//
// Set up nRF24L01 radio on SPI bus plus pins 7 & 8
RF24 radio(7,8);
// sets the role of this unit in hardware. Connect to GND to be the 'pong' receiver
// Leave open to be the 'ping' transmitter
const int role_pin = 5;
//
// Topology
//
// Radio pipe addresses for the 2 nodes to communicate.
const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };
//
// Role management
//
// Set up role. This sketch uses the same software for all the nodes
// in this system. Doing so greatly simplifies testing. The hardware itself specifies
// which node it is.
//
// This is done through the role_pin
//
// The various roles supported by this sketch
typedef enum { role_ping_out = 1, role_pong_back } role_e;
// The debug-friendly names of those roles
const char* role_friendly_name[] = { "invalid", "Ping out", "Pong back"};
// The role of the current running sketch
role_e role;
//
// Payload
//
const int min_payload_size = 4;
const int max_payload_size = 32;
const int payload_size_increments_by = 1;
int next_payload_size = min_payload_size;
char receive_payload[max_payload_size+1]; // +1 to allow room for a terminating NULL char
void setup(void)
{
//
// Role
//
// set up the role pin
pinMode(role_pin, INPUT);
digitalWrite(role_pin,HIGH);
delay(20); // Just to get a solid reading on the role pin
// read the address pin, establish our role
if ( digitalRead(role_pin) )
role = role_ping_out;
else
role = role_pong_back;
//
// Print preamble
//
Serial.begin(115200);
Serial.println(F("RF24/examples/pingpair_dyn/"));
Serial.print(F("ROLE: "));
Serial.println(role_friendly_name[role]);
//
// Setup and configure rf radio
//
radio.begin();
// enable dynamic payloads
radio.enableDynamicPayloads();
// optionally, increase the delay between retries & # of retries
radio.setRetries(5,15);
//
// Open pipes to other nodes for communication
//
// This simple sketch opens two pipes for these two nodes to communicate
// back and forth.
// Open 'our' pipe for writing
// Open the 'other' pipe for reading, in position #1 (we can have up to 5 pipes open for reading)
if ( role == role_ping_out )
{
radio.openWritingPipe(pipes[0]);
radio.openReadingPipe(1,pipes[1]);
}
else
{
radio.openWritingPipe(pipes[1]);
radio.openReadingPipe(1,pipes[0]);
}
//
// Start listening
//
radio.startListening();
//
// Dump the configuration of the rf unit for debugging
//
radio.printDetails();
}
void loop(void)
{
//
// Ping out role. Repeatedly send the current time
//
if (role == role_ping_out)
{
// The payload will always be the same, what will change is how much of it we send.
static char send_payload[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ789012";
// First, stop listening so we can talk.
radio.stopListening();
// Take the time, and send it. This will block until complete
Serial.print(F("Now sending length "));
Serial.println(next_payload_size);
radio.write( send_payload, next_payload_size );
// Now, continue listening
radio.startListening();
// Wait here until we get a response, or timeout
unsigned long started_waiting_at = millis();
bool timeout = false;
while ( ! radio.available() && ! timeout )
if (millis() - started_waiting_at > 500 )
timeout = true;
// Describe the results
if ( timeout )
{
Serial.println(F("Failed, response timed out."));
}
else
{
// Grab the response, compare, and send to debugging spew
uint8_t len = radio.getDynamicPayloadSize();
// If a corrupt dynamic payload is received, it will be flushed
if(!len){
return;
}
radio.read( receive_payload, len );
// Put a zero at the end for easy printing
receive_payload[len] = 0;
// Spew it
Serial.print(F("Got response size="));
Serial.print(len);
Serial.print(F(" value="));
Serial.println(receive_payload);
}
// Update size for next time.
next_payload_size += payload_size_increments_by;
if ( next_payload_size > max_payload_size )
next_payload_size = min_payload_size;
// Try again 1s later
delay(100);
}
//
// Pong back role. Receive each packet, dump it out, and send it back
//
if ( role == role_pong_back )
{
// if there is data ready
while ( radio.available() )
{
// Fetch the payload, and see if this was the last one.
uint8_t len = radio.getDynamicPayloadSize();
// If a corrupt dynamic payload is received, it will be flushed
if(!len){
continue;
}
radio.read( receive_payload, len );
// Put a zero at the end for easy printing
receive_payload[len] = 0;
// Spew it
Serial.print(F("Got response size="));
Serial.print(len);
Serial.print(F(" value="));
Serial.println(receive_payload);
// First, stop listening so we can talk
radio.stopListening();
// Send the final one back.
radio.write( receive_payload, len );
Serial.println(F("Sent response."));
// Now, resume listening so we catch the next packets.
radio.startListening();
}
}
}
// vim:cin:ai:sts=2 sw=2 ft=cpp