void setup(){
  Serial.begin(9600);
  size_t freeHeapSize = xPortGetFreeHeapSize();
  size_t minimumHeapSize = xPortGetMinimumEverFreeHeapSize();
  Serial.println("Before allocation : ");
  Serial.println(freeHeapSize);
  Serial.println(minimumHeapSize);
  char *s = (char*) pvPortMalloc(30);
  if(s){
    strcpy(s,"quanlybonho");
    freeHeapSize = xPortGetFreeHeapSize();
    size_t minimumHeapSize = xPortGetMinimumEverFreeHeapSize();
    Serial.println("After allocation : ");
    Serial.println(freeHeapSize);
    Serial.println(minimumHeapSize);
    vPortFree(s);
  }
}
void loop(){

}