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Rasp3.cpp

+/*
+ * See documentation at https://nRF24.github.io/RF24
+ * See License information at root directory of this library
+ * Author: Brendan Doherty (2bndy5)
+ */
+
+/**
+ * A simple example of sending data from 1 nRF24L01 transceiver to another.
+ *
+ * This example was written to be used on 2 devices acting as "nodes".
+ * Use `ctrl+c` to quit at any time.
+ */
+#include <ctime>       // time()
+#include <iostream>    // cin, cout, endl
+#include <string>      // string, getline()
+#include <time.h>      // CLOCK_MONOTONIC_RAW, timespec, clock_gettime()
+#include <RF24/RF24.h> // RF24, RF24_PA_LOW, delay()
+
+using namespace std;
+
+/****************** Linux ***********************/
+// Radio CE Pin, CSN Pin, SPI Speed
+// CE Pin uses GPIO number with BCM and SPIDEV drivers, other platforms use their own pin numbering
+// CS Pin addresses the SPI bus number at /dev/spidev<a>.<b>
+// ie: RF24 radio(<ce_pin>, <a>*10+<b>); spidev1.0 is 10, spidev1.1 is 11 etc..
+#define CSN_PIN 0
+#ifdef MRAA
+    #define CE_PIN 15 // GPIO22
+#else
+    #define CE_PIN 22
+#endif
+// Generic:
+RF24 radio(CE_PIN, CSN_PIN);
+/****************** Linux (BBB,x86,etc) ***********************/
+// See http://nRF24.github.io/RF24/pages.html for more information on usage
+// See http://iotdk.intel.com/docs/master/mraa/ for more information on MRAA
+// See https://www.kernel.org/doc/Documentation/spi/spidev for more information on SPIDEV
+
+float payload = -1; //
+
+void setRole(); // set the node's role
+void master();  // TX node's behavior
+void slave();   // RX node's behavior
+
+// custom defined timer for evaluating transmission time in microseconds
+struct timespec startTimer, endTimer;
+uint32_t getMicros(); // prototype to get elapsed time in microseconds
+
+int main(int argc, char** argv)
+{
+
+    // perform hardware check
+    if (!radio.begin()) {
+        cout << "radio hardware is not responding!!" << endl;
+        return 0; // quit now
+    }
+
+    // A variable to uniquely identify which address this radio will use to transmit and receive
+    bool radioNumber = 1; // 0 uses address[0] to transmit, 1 uses address[1] to transmit and the other one uses to receive
+
+    // print program's name
+    cout << argv[0] << endl;
+
+    // Let these addresses be used for the pair
+    uint8_t address[2][6] = {"LIFT1", "SPEAK"};
+
+    // Set the radioNumber via the terminal on startup. It will change the transmit direction. 1 for LIFT to BUS, 0 for BUS to LIFT
+    string input;
+    input.assign(argv[1]);
+    radioNumber = input.length() > 0 && (uint8_t)input[0] == 49;
+
+    // save on transmission time by setting the radio to only transmit the
+    // number of bytes we need to transmit a float
+    radio.setPayloadSize(sizeof(payload)); // float datatype occupies 4 bytes
+
+    // Set the PA Level low to try preventing power supply related problems
+    // because these examples are likely run with nodes in close proximity to
+    // each other.
+    radio.setPALevel(RF24_PA_LOW); // RF24_PA_MAX is default.
+
+
+    radio.openWritingPipe(address[radioNumber]); // using pipe 0
+    radio.openReadingPipe(1, address[!radioNumber]); // using pipe 1
+
+    // For debugging info
+    // radio.printDetails();       // (smaller) function that prints raw register values
+    // radio.printPrettyDetails(); // (larger) function that prints human readable data
+
+    // ready to execute program now
+    setRole(); // calls master() and slave() one after another
+    return 0;
+}
+
+/**
+ * Role of this program will pingpong.
+ */
+void setRole()
+{
+    while(1){
+        master();
+        slave();
+    }
+} // setRole()
+
+/**
+ * make this node act as the transmitter
+ */
+void master()
+{
+    radio.stopListening(); // put radio in TX mode
+
+    cout << "Start TX role." << endl;
+
+    unsigned int mcount = 0; // keep track of master time
+    while (mcount < 2 && payload != 1) { // if not received any values since last transmit no transmition
+        clock_gettime(CLOCK_MONOTONIC_RAW, &startTimer);    // start the timer
+        bool report = radio.write(&payload, sizeof(float)); // transmit & save the report
+        uint32_t timerElapsed = getMicros();                // end the timer
+
+        if (report) {
+            // payload was delivered
+            cout << "Transmission successful! Time to transmit = ";
+            cout << timerElapsed;                     // print the timer result
+            cout << " us. Sent: " << payload << endl; // print payload sent
+            if(mcount >= 2){
+                payload = -1;
+            }
+        }
+        else {
+            // payload was not delivered
+            cout << "Transmission failed or timed out" << endl;
+        }
+        mcount++;
+        // to make this program readable in the terminal
+        delay(1000); // slow transmissions down by 1 second
+    }
+    cout << "Leaving TX role.\n" << endl;
+}
+
+/**
+ * make this node act as the receiver
+ */
+void slave()
+{
+
+    radio.startListening(); // put radio in RX mode
+
+    cout << "Start RX role." << endl;
+
+    time_t startTimer = time(nullptr);       // start a timer
+    while (time(nullptr) - startTimer < 6) { // use 6 second timeout
+        uint8_t pipe;
+        if (radio.available(&pipe)) {                        // is there a payload? get the pipe number that recieved it
+            uint8_t bytes = radio.getPayloadSize();          // get the size of the payload
+            radio.read(&payload, bytes);                     // fetch payload from FIFO
+            cout << "Received ";                             // print the size of the payload
+            cout << ": " << payload << endl;                 // print the payload's value
+        }
+    } //After 6 seconds of listening convert to transmiter again
+    cout << "Leaving RX role.\n" << endl;
+    radio.stopListening();
+}
+
+/**
+ * Calculate the elapsed time in microseconds
+ */
+uint32_t getMicros()
+{
+    // this function assumes that the timer was started using
+    // `clock_gettime(CLOCK_MONOTONIC_RAW, &startTimer);`
+
+    clock_gettime(CLOCK_MONOTONIC_RAW, &endTimer);
+    uint32_t seconds = endTimer.tv_sec - startTimer.tv_sec;
+    uint32_t useconds = (endTimer.tv_nsec - startTimer.tv_nsec) / 1000;
+
+    return ((seconds)*1000 + useconds) + 0.5;
+}