arduino_baud_rate_detection

arduino_baud_rate_detection.ino

/*
  casy na seriovem portu: https://www.kumari.net/index.php/random/37-determing-unknown-baud-rate
  
  Odmeroval jsem je Saleae logickym analyzatorem
*/

int last_baud_rate = 9600;
int timeout = 1000; // [ms]

int recPin = 0;  //the pin receiving the serial input data

long baudRate;

void set_serial_port() {
  Serial.end();
  
  digitalWrite (recPin, HIGH); // pull up enabled just for noise protection
 
  baudRate = detRate(recPin);  // Function finds a standard baudrate of either
                               // 1200,2400,4800,9600,14400,19200,28800,38400,57600,115200 
                               // by having sending circuit send "U" characters.
                               // Returns 0 if none or under 1200 baud  
  Serial.begin(baudRate);
  Serial.println();
  Serial.print("Detected baudrate at ");
  Serial.println(baudRate);  
}

void setup() {
  pinMode(recPin, INPUT);      // make sure serial in is a input pin
  set_serial_port();
}

void loop() { 
  set_serial_port();

  Serial.println("Hello, world!");

  delay(2000);
}

long detRate(int recpin)  // function to return valid received baud rate
                         // Note that the serial monitor has no 600 baud option and 300 baud
                         // doesn't seem to work with version 22 hardware serial library
 {
  while(digitalRead(recpin) == 1){} // wait for low bit to start
  long baud;
  long rate = pulseIn(recpin,LOW);   // measure zero bit width from character 'U'
    if (rate < 0)
      baud = 0;

     else if (rate < 4)
      baud = 500000;   
     else if (rate < 6)
      baud = 230400;          
     else if (rate < 12)
      baud = 115200;
     else if (rate < 20)
       baud = 57600;
     else if (rate < 29)
       baud = 38400;
     else if (rate < 40)
      baud = 28800;
     else if (rate < 60)
      baud = 19200;
     else if (rate < 80)
      baud = 14400;
     else if (rate < 150)
       baud = 9600;
     else if (rate < 300)
       baud = 4800;
     else if (rate < 600)
       baud = 2400;
     else if (rate < 1200)
       baud = 1200;
     else 
       baud = 0;  
  return baud; 
 }