树莓派与Arduino Leonardo使用NRF24L01无线模块通信之基于RF24库 (三) 全双工通信

设计思路

Arduino Leonardo初始化为发送模式，发送完成后，立即切换为接收模式，不停的监听，收到数据后立即切换为发送模式，若超过一定时间还为接收到数据，则切换为发送模式。

树莓派初始化为接收模式，接收到数据后立即切换为发送模式，超过一定时间为接收到数据则切换为发送模式，发送数据后立即切换为接收模式。

代码实现

Arduino Leonardo代码

如下：

#include <SPI.h>
#include "RF24.h"
#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(9,10);
/**********************************************************/

byte addresses[][6] = {"1Node","2Node"};

// Used to control whether this node is sending or receiving
bool role = 1;//1表示发送模式，0表示接收模式
unsigned long start_time = micros();

//这个是我们即将建立的传输渠道编码
//!!要和另一个模块的一致
const uint64_t pipes = 0xE8E8F0F0E1LL;
 
//这个变量会保持我们接受到的信息
//变量类型一定要和传过来的一样
//要传输的数据
unsigned long sendData = 1;
unsigned long head = 0x01000000;//高8位为头标志，根据标志不同区分不同发送源，0x00为中心主节点
unsigned long receData;

void setup() {
  pinMode(13,OUTPUT);//指示灯
  Serial.begin(57600);
  printf_begin();
  Serial.println(F("RF24/examples/GettingStarted"));
  
  radio.begin();

  radio.setPALevel(RF24_PA_MAX);
  radio.openWritingPipe(pipes);
  
}

void loop() {
   Serial.print("role:");
   Serial.println(role);
  if(role){
     unsigned long data = sendData+head;
     Serial.print("Sending:");
     Serial.println(data);
     digitalWrite(13,HIGH);
     bool ok = radio.write(&data,sizeof(unsigned long));

     
       role = 0; 
       radio.openReadingPipe(1,pipes);
       radio.startListening();
       start_time = micros();
     
  }
  if(!role){
     digitalWrite(13,LOW);
     if(radio.available()){
         radio.read(&receData,sizeof(unsigned long));
         Serial.print("Response:");
         Serial.println(receData);
         role = 1;
         radio.stopListening();
         radio.openWritingPipe(pipes);
     }else{
        unsigned long end_time = micros();
        if((end_time-start_time)>=1000){
          role = 1;
          radio.stopListening();
          radio.openWritingPipe(pipes);
        }
     }
  }
  
} // Loop

树莓派代码

如下：

#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>
#include <RF24/RF24.h>

using namespace std;
//
// Hardware configuration
// Configure the appropriate pins for your connections

/****************** Raspberry Pi ***********************/

// Radio CE Pin, CSN Pin, SPI Speed
// See http://www.airspayce.com/mikem/bcm2835/group__constants.html#ga63c029bd6500167152db4e57736d0939 and the related enumerations for pin information.

// Setup for GPIO 22 CE and CE0 CSN with SPI Speed @ 4Mhz
//RF24 radio(RPI_V2_GPIO_P1_22, BCM2835_SPI_CS0, BCM2835_SPI_SPEED_4MHZ);

// NEW: Setup for RPi B+
//RF24 radio(RPI_BPLUS_GPIO_J8_15,RPI_BPLUS_GPIO_J8_24, BCM2835_SPI_SPEED_8MHZ);

// Setup for GPIO 15 CE and CE0 CSN with SPI Speed @ 8Mhz
//RF24 radio(RPI_V2_GPIO_P1_15, RPI_V2_GPIO_P1_24, BCM2835_SPI_SPEED_8MHZ);

// RPi generic:
RF24 radio(22,0);

/*** RPi Alternate ***/
//Note: Specify SPI BUS 0 or 1 instead of CS pin number.
// See http://tmrh20.github.io/RF24/RPi.html for more information on usage

//RPi Alternate, with MRAA
//RF24 radio(15,0);

//RPi Alternate, with SPIDEV - Note: Edit RF24/arch/BBB/spi.cpp and  set 'this->device = "/dev/spidev0.0";;' or as listed in /dev
//RF24 radio(22,0);


/****************** Linux (BBB,x86,etc) ***********************/

// See http://tmrh20.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

// Setup for ARM(Linux) devices like BBB using spidev (default is "/dev/spidev1.0" )
//RF24 radio(115,0);

//BBB Alternate, with mraa
// CE pin = (Header P9, Pin 13) = 59 = 13 + 46 
//Note: Specify SPI BUS 0 or 1 instead of CS pin number. 
//RF24 radio(59,0);

/********** User Config *********/
// Assign a unique identifier for this node, 0 or 1
bool radioNumber = 1;
bool role = 0;//receive mode
unsigned long  start_time=millis();
unsigned long count=0;
/********************************/

// Radio pipe addresses for the 2 nodes to communicate.
const uint64_t pipes = 0xE8E8F0F0E1LL;

unsigned long  receData;
unsigned long  respData=0x01;
unsigned long  head=0x00000000;
int main(int argc, char** argv){

  cout << "RF24/examples/GettingStarted/
";

  // Setup and configure rf radio
  radio.begin();
  // optionally, increase the delay between retries & # of retries
  radio.setRetries(15,15);
  // Dump the configuration of the rf unit for debugging
  radio.printDetails();
  
  radio.openReadingPipe(1,pipes);
/***********************************/
  // This simple sketch opens two pipes for these two nodes to communicate
  // back and forth.

  radio.startListening();

  cout << "Listening .... 
";
  // forever loop
  while (1)
  {
  // Pong back role.  Receive each packet, dump it out, and send it back
  //
    if(!role){
        if(radio.available()){
            count++;
            radio.read(&receData,sizeof(unsigned long));
            printf("Get Data:size(%d),count(%lu) %lu 
",sizeof(unsigned long),count,receData);
            role = 1;
            radio.stopListening();
            radio.openWritingPipe(pipes);
        }else{
            unsigned long end_time = millis();
            if((end_time-start_time)>=1000){
                role = 1;
                radio.stopListening();
                radio.openWritingPipe(pipes);
            }
        }
    }
    if(role){
        unsigned long data = respData + head;
        radio.write(&data,sizeof(unsigned long));
        printf("Send Data:size(%d),%lu 
",sizeof(unsigned long),data);
        role = 0;
        radio.startListening();
        radio.openReadingPipe(1,pipes);
        start_time = millis();
    }

  } // forever loop

  return 0;
}