If statement problem

Projects Programming
1

Hi all
I have a problem where I am waiting for a command from a PC serial port. Once the command comes in I run through some if statements

The structure of the commands is all basically the same eg "cu50". The problem I have is It sees it matches two things both cu5 and cu50.

Any ideas would be much appreciated

while (Serial.available()) {
    delay(1);  //delay to allow buffer to fill 
    if (Serial.available() >0) {
      char c = Serial.read();  //gets one byte from serial buffer
      readString += c; //makes the string readString
         
    if(readString=="?VS"){
        Serial.println("Box C");        
      }
     if(readString=="*IDN?"){
        Serial.println("Box C Voltage hybrid burden box");        
      }
    if(readString=="?SN"){
        Serial.println("Box C IP003");        
      }
    
     if(readString=="cu2.5"){               
        bdn = readString.substring(2,7);
        Unity2_5();
        Serial.println(bdn); 
        }
      if(readString=="cu5"){               
        bdn = readString.substring(2,7);
        Unity2_5();
        Serial.println(bdn); 
        }
        if(readString=="cu7.5"){               
        bdn = readString.substring(2,7);
        Unity2_5();
        Serial.println(bdn); 
        }
      if(readString=="cu10"){               
        bdn = readString.substring(2,7);
        Unity2_5();
        Serial.println(bdn); 
        }
        if(readString=="cu50"){               
        bdn = readString.substring(2,7);
        Unity2_5();
        Serial.println(bdn); 
        }

    }
 }     
//bdn = "";  
readString="";
Serial.flush();
2

The problem is the command is coming in one character at a time and you run through those if statements after each character. You should receive the entire string before running the if statements.

3

Cheers FIXED, this is what happens when you cut and paste.

4

Cheers FIXED, this is what happens when you cut and paste.

Please, post your modified codes that you managed to work following the message of Post#1. We are interested, for the benefit of other Forum Members, to get familiar with your programming style of catching the string ?VS (for example) and then taking decision.

Thanks,

5

It is not a good idea to use the String (capital S) class on an Arduino as it can cause memory corruption in the small memory on an Arduino. Just use cstrings - char arrays terminated with 0.

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data. There is also a parse example.
...R