/* * 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 #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