Serial.read() help

Forum 2005-2010 (read only) Software Syntax & Programs
11

I've been manipulating and rewriting both programs to no avail. In the first program i used i just don't understand why the serial read is "232230", but after atoi it's some oddball negative number.

I tried using this program

#include <stdlib.h>    
char X_buffer[3];
char Y_buffer[3];
int received;
int i=0;
int X_pos=0;
int Y_pos=0;

void setup()
{
    Serial.begin(57600);
    received = 0;
    X_buffer[received] = '\0';
    Y_buffer[received] = '\0';
    Serial.println("setup");
}
void loop()
{
    if (Serial.available())
    {
      // Get x cord
        for(i=0; i<3; i++)
          {
          X_buffer[i] = Serial.read();
          }
        // Get y cord
        for(i=0; i<3; i++)
          {
          Y_buffer[i] = Serial.read();
          }
      X_pos = atoi(X_buffer);
      Y_pos = atoi(Y_buffer);



  Serial.print("x:");
  Serial.print(X_pos);
  Serial.print("y:");
  Serial.print(Y_pos);
  Serial.println();

 }
}

with output

setup

x:2y:0

x:32230y:30

x:2y:0

x:-32306y:30

x:2y:0

x:32230y:30

x:2y:0

x:32230y:30

correct output should have been "232230"

i'm sending the data by:

    Serial.print((int)chuck.readJoyX()*-1+100); //make is positive and always 3 digits long
   // Serial.print(",jy ");  
    Serial.print((int)chuck.readJoyY()*-1+100); //make is positive and always 3 digits long

i've tried taking out the (int) makes no difference. I'm sending it as integer ascii?

here's the original program output

setup

*232230*-29914*

*233230*-28914*

*232230*-29914*

*232230*-29914*

it's getting the right 232230... after atoi it's unusable