Multiple serial port not working

Projects Programming
1

This is working for me. I get data when I upload sketch https://electrosome.com/em-18-rfid-reader-arduino-uno/

int count = 0;                                          // count = 0
char input[12];                                         // character array of size 12 
boolean flag = 0;                                       // flag =0
void setup()
{
   Serial.begin(9600);                                  // begin serial port with baud rate 9600bps
}
void loop()
{
   if(Serial.available())
   {
      count = 0;
      while(Serial.available() && count < 12)          // Read 12 characters and store them in input array
      {
         input[count] = Serial.read();
         count++;
         delay(5);
      }
      Serial.print(input);                             // Print RFID tag number 
      
      if((input[0] ^ input[2] ^ input[4] ^ input[6] ^ input[8] == input[10]) && 
         (input[1] ^ input[3] ^ input[5] ^ input[7] ^ input[9] == input[11]))
            Serial.println("No Error");
      else
            Serial.println("Error");      
   }
}

Above code only work for hardware serial but I need to read multiple port to read many RFIDS

I found this link https://docs.arduino.cc/tutorials/communication/TwoPortReceive

I don't get reader data when I upload below sketch

#include <SoftwareSerial.h>
// software serial #1: RX = digital pin 10, TX = digital pin 11

SoftwareSerial portOne(10, 11);

// software serial #2: RX = digital pin 8, TX = digital pin 9
// on the Mega, use other pins instead, since 8 and 9 don't work on the Mega

SoftwareSerial portTwo(8, 9);

void setup() {

  // Open serial communications and wait for port to open:

  Serial.begin(9600);

  while (!Serial) {

    ; // wait for serial port to connect. Needed for native USB port only

  }

  // Start each software serial port

  portOne.begin(9600);

  portTwo.begin(9600);
}

void loop() {

  // By default, the last initialized port is listening.

  // when you want to listen on a port, explicitly select it:

  portOne.listen();

  Serial.println("Data from port one:");

  // while there is data coming in, read it

  // and send to the hardware serial port:

  while (portOne.available() > 0) {

    char inByte = portOne.read();

    Serial.write(inByte);

  }

  // blank line to separate data from the two ports:

  Serial.println();

  // Now listen on the second port

  portTwo.listen();

  // while there is data coming in, read it

  // and send to the hardware serial port:

  Serial.println("Data from port two:");

  while (portTwo.available() > 0) {

    char inByte = portTwo.read();

    Serial.write(inByte);

  }

  // blank line to separate data from the two ports:

  Serial.println()
2

Did you read this?

Limitations of This Library

SoftwareSerial library has the following known limitations:

[...]
If using multiple software serial ports, only one can receive data at a time.

1 Like
3

Change your hardware. A Mega2560 has 4 hardware serial interfaces.

1 Like
4

i know but why my code is not working. I have written program for two port but i am testing only one rfid so i was expecting it should be work

5

Perhaps your device does not know it is connected. Are you using the actual pins associated with that particular software serial set up?

6

You didn't upload a complete sketch.

7

Yes

I have uploaded the complete sketch given in link and after compiling I saw there was no error.

Sketch is posted on the forum from mobile, so there may be some mistakes

8

I have uploaded below sketch but it doesn't display data on serial monitor. Do I have to use array to store 12 bit data in code ?

#include <SoftwareSerial.h>

// Set up a new SoftwareSerial object with RX in digital pin 10 and TX in digital pin 11
SoftwareSerial mySerial(10, 11);

void setup() {
    // Set the baud rate for the SerialSoftware object
    mySerial.begin(9600);
}

void loop() {
    char c = mySerial.read();
}
9

There are no serial print() or write() calls, so that isn't a surprise.

10

Done but still not getting data on serial monitor

#include <SoftwareSerial.h>

#define rxPin 10
#define txPin 11

// Set up a new SoftwareSerial object
SoftwareSerial mySerial =  SoftwareSerial(rxPin, txPin);

void setup()  {
    // Define pin modes for TX and RX
    pinMode(rxPin, INPUT);
    pinMode(txPin, OUTPUT);
    
    // Set the baud rate for the SoftwareSerial object
    mySerial.begin(9600);
}

void loop() {
    if (mySerial.available() > 0) {
        mySerial.read();
        char c = mySerial.read();
        Serial.write(c);
        mySerial.print(c);
    }
}
11

This could print a strange char for each character received, if there were a Serial.begin.

12

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.