Serial.readBytes length issue

[STRLTech]

Hello there,
I am using my Duemilanove (ATMEGA 328) with IDE v.1.05-r2
I am trying to read my serial buffer and store 12 bytes of data into 3 variables (4 bytes each, converted into single integers. However, the read function is not stopping at the correct length.

Example:
input 123456789012
output:
123456789012
56789012
9012
from the three variables, respectively. If i set the read length to anything other than 4 (i tried 3 and 2), it works fine.

any suggestions?
Thanks

void datachk() {
 if(Serial.available() > 11) {
    Serial.readBytes(grn, 4);
    Serial.readBytes(ylw, 4);
    Serial.readBytes(rd, 4);
    int green = atoi(grn);
    int yellow = atoi(ylw);
    int red = atoi(rd);
    if((green < 6000) && (green >= 0) && (yellow >= 0) && (red >= 0) && (yellow < green) && (red < yellow)) {
      countdown(green, yellow, red);
    } else {
      Serial.println(grn);
      Serial.println(ylw);
      Serial.println(rd);
      Serial.println("Invalid Times.");
    }
  } 
}

[Robin2]

Write a short sketch that just reads the 3 chunks into three character variables and prints them out. If it is not working properly post the full sketch - and please post the sketch within code tags (the # button) rather than quote tags.

...R

[STRLTech]

My mistake on the quote tags (long night).
Interesting, if i put:

Code: [Select]

char grn[4];
char ylw[4];
char rd[4];

void setup () {
  Serial.begin(9600);
}

void loop() {
if(Serial.available() > 11) {
    Serial.readBytes(grn, 4);
    Serial.readBytes(ylw, 4);
    Serial.readBytes(rd, 4);
    Serial.println(grn);
    Serial.println(ylw);
    Serial.println(rd);
  }
}
and enter: 123456789012
it reads back:
123456789012123456789012
56789012123456789012
9012123456789012

[Robin2]

You need to declare each of the colours as 5 chars and the last byte must be 0. That's how C/C++ defines strings. At the moment Serial.print has no means of knowing the end of the any of the colour variables.

...R

[STRLTech]

Aha. That worked perfectly. Thank you very much