Arduino uno serial communication

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hi i a using arduino uno to send data serially to visual basic.
the problem is it keeps sending the data continuously.
i want the arduino to send data only once.
please help

What I have tried:

#include <softwareserial.h>
/*-----( Declare Constants and Pin Numbers )-----*/
#define SSerialRX 10 //Serial Receive pin
#define SSerialTX 11 //Serial Transmit pin

#define SSerialTxControl 3 //RS485 Direction control
#define RS485Transmit HIGH
#define RS485Receive LOW
int ledpin = 13;
/*-----( Declare objects )-----*/
SoftwareSerial RS485Serial(SSerialRX, SSerialTX); // RX, TX

/*-----( Declare Variables )-----*/
int byteReceived;
int byteSend;

void setup() /****** SETUP: RUNS ONCE ******/
{
// Start the built-in serial port, probably to Serial Monitor
Serial.begin(9600);
Serial.println("SerialRemote"); // Can be ignored
pinMode(SSerialTxControl, OUTPUT);
digitalWrite(SSerialTxControl, RS485Receive); // Init Transceiver

// Start the software serial port, to another device
RS485Serial.begin(9600); // set the data rate
pinMode(ledpin,OUTPUT);
digitalWrite(ledpin,LOW);
}//--(end setup )---

void loop() /****** LOOP: RUNS CONSTANTLY ******/
{
//Copy input data to output
if (RS485Serial.available())
{
digitalWrite(ledpin,HIGH);
byteReceived = RS485Serial.read(); // Read the byte
Serial.write(byteReceived); // Show on Serial Monitor

}
}

}//--(end main loop )---

/*-----( Declare User-written Functions )-----*/
//NONE

//*********( THE END )***********

Posted 8-Mar-16 16:44pm

Member 12299248

Updated 7-Feb-18 4:28am

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Syed Zain Nasir · Answer 1 · 2016-10-15T19:34:00

Solution 2

If you want to send the data just once then you should place your code in void setup(){} loop because it will be executed only once.

Posted 15-Oct-16 19:34pm

Syed Zain Nasir

Comments

[no name] 16-Oct-16 7:15am

You mean do it just like solution 1 said?

Mircea Diaconescu · Answer 2 · 2016-04-21T23:04:00

It send data continuously because of this line

C++

Serial.write(byteReceived);

from your "loop" method. The loop method executes again and again...is just what is there for.
If you want this to be executed just once, put that code line in "setup" or, if that is not possible for any reason, then just make a flag that control its execution, so it only executes once in the "loop".

glennPattonWork3 · Answer 3 · 2018-02-07T04:28:00

Ummm, not a good thing to place code in setup(). change the if() to something other that the RS485.available() this is why because your device is sending data constantly sending
data you could send a command to the device to be quiet. If use a Bool to check and set once your program has recieved the data.

Quote:

C++

bool bSet = false;
-----
void loop{

if (bSet == false) && (RS485Serial.available == true)
{
   bSet = true; // too prevent retrigger
   Serial.write(byteReceived); 
}
}

or after the loop in user defined functions something like:

Quote:

C++

bool bSet = false;
-----
void loop{

if (bSet == false) && (RS485Serial.available == true)
{
   bSet = true; // too prevent retrigger
   ReadMe(); 
}
}

}
}


}//--(end main loop )---

/*-----( Declare User-written Functions )-----*/
void ReadMe(){

Serial.write(byteReceived); // Show on Serial Monitor

}

Arduino uno serial communication

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