My code can receive data serially from PIC16F877A.
Sometimes, random and unnecessary data are received. If i use tinyBootloader's serial receiver, it picks up required data. Immediately after closing tinyBootloader, if i run my code, then my program also receives that data. Is there something wrong with my code's port opening and closing. Please help.
Here's that code...
Qt Code: 
  1. #include "mainwindow.h"
  2. #include "ui_mainwindow.h"
  3. #include "qextserialport.h"
  4. #include <QTimer>
  5.  
  6. MainWindow::MainWindow(QWidget *parent) :
  7.     QMainWindow(parent),
  8.     ui(new Ui::MainWindow)
  9. {
  10.     ui->setupUi(this);
  11.     QString com;
  12.     com = ui->comboBox->currentText();
  13.     port = new QextSerialPort(com);
  14.     port->setBaudRate(BAUD9600);
  15.     port->setFlowControl(FLOW_OFF);
  16.     port->setParity(PAR_NONE);
  17.     port->setDataBits(DATA_8);
  18.     port->setStopBits(STOP_1);
  19.     ui->dataWindow1->setDisabled(1);
  20.     ui->dataWindow2->setDisabled(1);
  21.     if(port->isOpen())
  22.     {
  23.         port->flush();
  24.         port->close();
  25.     }
  26.     QTimer *timer = new QTimer(this);
  27.     connect(timer, SIGNAL(timeout()), this, SLOT(serialupdate()));
  28.     timer->start(100);
  29. }
  30.  
  31. MainWindow::~MainWindow()
  32. {
  33.     port->close();
  34.     delete ui;
  35.     delete port;
  36. }
  37.  
  38.  
  39. void MainWindow::serialupdate()
  40. {
  41.     port->flush();
  42.     char buff[1024];
  43.     if(port->bytesAvailable())
  44.     {
  45.         int i = port->read(buff, 1);
  46.         buff[i] = '\0';
  47.         if(i != -1)
  48.         {
  49.               QString str(buff);
  50.               QByteArray data = str.toAscii().toHex();
  51.               ui->dataWindow1->append("0x"+data);
  52.               ui->dataWindow2->append(str);
  53.         }
  54.         else
  55.             qDebug("cannot open");
  56.     }
  57. }
  58.  
  59. void MainWindow::on_pushButton_clicked()
  60. {
  61.     ui->dataWindow1->setDisabled(0);
  62.     ui->dataWindow2->setDisabled(0);
  63.     ui->comboBox->setDisabled(1);
  64.     ui->comboBox_2->setDisabled(1);
  65.     port->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
  66. }
  67.  
  68. void MainWindow::on_pushButton_2_clicked()
  69. {
  70.     ui->dataWindow1->setDisabled(1);
  71.     ui->dataWindow2->setDisabled(1);
  72.     ui->comboBox->setDisabled(0);
  73.     ui->comboBox_2->setDisabled(0);
  74.     port->close();
  75. }
  76.  
  77.  
  78.  
  79. void MainWindow::on_pushButton_3_clicked()
  80. {
  81.     ui->dataWindow1->clear();
  82.     ui->dataWindow2->clear();
  83. }
  84.  
  85. void MainWindow::on_comboBox_2_currentIndexChanged(int index)
  86. {
  87.         if(index == 0)
  88.             port->setBaudRate(BAUD4800);
  89.         if(index == 1)
  90.             port->setBaudRate(BAUD9600);
  91.         if(index == 2)
  92.             port->setBaudRate(BAUD14400);
  93.         if(index == 3)
  94.             port->setBaudRate(BAUD19200);
  95.  }
To copy to clipboard, switch view to plain text mode