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/*
* Getting Started example sketch for nRF24L01+ radios* This is a very basic example of how to send data from one node to another* but modified to include failure handling.* * The nrf24l01+ radios are fairly reliable devices, but on breadboards etc, with inconsistent wiring, failures may* occur randomly after many hours to days or weeks. This sketch demonstrates how to handle the various failures and* keep the radio operational.* * The three main failure modes of the radio include:* Writing to radio: Radio unresponsive - Fixed internally by adding a timeout to the internal write functions in RF24 (failure handling)* Reading from radio: Available returns true always - Fixed by adding a timeout to available functions by the user. This is implemented internally in RF24Network.* Radio configuration settings are lost - Fixed by monitoring a value that is different from the default, and re-configuring the radio if this setting reverts to the default.* * The printDetails output should appear as follows for radio #0:* * STATUS = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0* RX_ADDR_P0-1 = 0x65646f4e31 0x65646f4e32* RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6* TX_ADDR = 0x65646f4e31* RX_PW_P0-6 = 0x20 0x20 0x00 0x00 0x00 0x00* EN_AA = 0x3f* EN_RXADDR = 0x02* RF_CH = 0x4c* RF_SETUP = 0x03* CONFIG = 0x0f* DYNPD/FEATURE = 0x00 0x00* Data Rate = 1MBPS* Model = nRF24L01+* CRC Length = 16 bits* PA Power = PA_LOW**Users can use this sketch to troubleshoot radio module wiring etc. as it makes the radios hot-swapable** Updated: 2019 by TMRh20*/
#include <SPI.h>
#include "RF24.h"
#include "printf.h"
/****************** User Config ***************************//*** Set this radio as radio number 0 or 1 ***/bool radioNumber = 0;
/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */RF24 radio(7,8);/**********************************************************/
byte addresses[][6] = {"1Node","2Node"};
// Used to control whether this node is sending or receiving
bool role = 0;
/**********************************************************///Function to configure the radio
void configureRadio(){
radio.begin();
// Set the PA Level low to prevent power supply related issues since this is a
// getting_started sketch, and the likelihood of close proximity of the devices. RF24_PA_MAX is default.
radio.setPALevel(RF24_PA_LOW); // Open a writing and reading pipe on each radio, with opposite addresses
if(radioNumber){ radio.openWritingPipe(addresses[1]); radio.openReadingPipe(1,addresses[0]); }else{ radio.openWritingPipe(addresses[0]); radio.openReadingPipe(1,addresses[1]); } // Start the radio listening for data
radio.startListening(); radio.printDetails();}
/**********************************************************/
void setup() { Serial.begin(115200); Serial.println(F("RF24/examples/GettingStarted")); Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));
printf_begin(); configureRadio(); }
uint32_t configTimer = millis();
void loop() { if(radio.failureDetected){ radio.failureDetected = false; delay(250); Serial.println("Radio failure detected, restarting radio"); configureRadio(); } //Every 5 seconds, verify the configuration of the radio. This can be done using any
//setting that is different from the radio defaults.
if(millis() - configTimer > 5000){ configTimer = millis(); if(radio.getDataRate() != RF24_1MBPS){ radio.failureDetected = true; Serial.print("Radio configuration error detected"); } } /****************** Ping Out Role ***************************/ if (role == 1) { radio.stopListening(); // First, stop listening so we can talk.
Serial.println(F("Now sending"));
unsigned long start_time = micros(); // Take the time, and send it. This will block until complete
if (!radio.write( &start_time, sizeof(unsigned long) )){ Serial.println(F("failed")); } radio.startListening(); // Now, continue listening
unsigned long started_waiting_at = micros(); // Set up a timeout period, get the current microseconds
boolean timeout = false; // Set up a variable to indicate if a response was received or not
while ( ! radio.available() ){ // While nothing is received
if (micros() - started_waiting_at > 200000 ){ // If waited longer than 200ms, indicate timeout and exit while loop
timeout = true; break; } } if ( timeout ){ // Describe the results
Serial.println(F("Failed, response timed out.")); }else{ unsigned long got_time; // Grab the response, compare, and send to debugging spew
//Failure Handling:
uint32_t failTimer = millis(); while(radio.available()){ //If available always returns true, there is a problem
if(millis() - failTimer > 250){ radio.failureDetected = true; Serial.println("Radio available failure detected"); break; } radio.read( &got_time, sizeof(unsigned long) ); } unsigned long end_time = micros(); // Spew it
Serial.print(F("Sent ")); Serial.print(start_time); Serial.print(F(", Got response ")); Serial.print(got_time); Serial.print(F(", Round-trip delay ")); Serial.print(end_time-start_time); Serial.println(F(" microseconds")); }
// Try again 1s later
delay(1000); }
/****************** Pong Back Role ***************************/
if ( role == 0 ) { unsigned long got_time; if( radio.available()){ uint32_t failTimer = millis(); // Variable for the received timestamp
while (radio.available()) { // While there is data ready
if(millis()-failTimer > 500){ Serial.println("Radio available failure detected"); radio.failureDetected = true; break; } radio.read( &got_time, sizeof(unsigned long) ); // Get the payload
} radio.stopListening(); // First, stop listening so we can talk
radio.write( &got_time, sizeof(unsigned long) ); // Send the final one back.
radio.startListening(); // Now, resume listening so we catch the next packets.
Serial.print(F("Sent response ")); Serial.println(got_time); } }
/****************** Change Roles via Serial Commands ***************************/
if ( Serial.available() ) { char c = toupper(Serial.read()); if ( c == 'T' && role == 0 ){ Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK")); role = 1; // Become the primary transmitter (ping out)
}else if ( c == 'R' && role == 1 ){ Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK")); role = 0; // Become the primary receiver (pong back)
radio.startListening(); } }
} // Loop
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