know the buffer size of an incoming serial data?

Forum 2005-2010 (read only) Software Syntax & Programs
1

hello all , here i go with my noob question

i need to know the size of the incoming serial data to set a char buffer.

im working with an xport which retrieves some data from a web site , the response may be variable from response to response, and i display it in an LCD 16x2 chars, because the response is so long i need to store the serial data in a string var and display it with a delay so the word would be easy to read. (i think that might be a relative decent solution to this problem)

im using the PString.h library[1] to store the response in a variable, value that is assigned in a while method, the code is the following:

//.... after the get || post request of the xport 

char buffer[330];
PString str(buffer, sizeof(buffer));
str = ""; // assignment
int stop = 1;
int buffer_size = 0;
 while (stop == 1 )
{
  if (mySerial.available()){
      str += (char)mySerial.read(); // concatenation
  }else {
     str +=mySerial.read(); 
    if(mySerial.read()==-1   ){
      stop = 0;
    }
  }
}

   Serial.println("print the response");
  Serial.print(str);

the response prints ok, but i have one problem. i dont get all the data printed because i set the buffer in a < number than the serial response.
my question is: how can a get the number to set the buffer propperly to get all the response? if a set with a > number of the response then the the data dont prints et all.

i hope you can help me with this. :slight_smile:

sorry for the bad english BTW

cheers

[1] http://arduiniana.org/

2

mySerial.available () is a function that returns the number of bytes available. Since you are just using its result in a boolean evaluation, your code is simply checking whether it is greater than zero or not.

You want to use the result of that function to decide how many bytes to read, if it is greater than zero.