Hi,
I have two quesitons.
-
I read that Serial.flush no longer empties the incoming buffer. I bought the "Arduino Cookbook by Michael Margolis and I am trying to understand the example code and do the experiment. Serial.flush is part of his program. Is there a replacement for this? However I still tried the experiment and it works with Serial.flush.
-
In the same experiment, the function: boolean configureRadio() either returns a “true” or “false” ? Is this like an if statement, in that if the function returns a true, then the rest of the program runs. If the function returns a false, then the function starts over again until it returns a true?
Thank you very much 
Here is the code:
/*
XBeeAnalogReceiveSeries1
Read an analog value from an XBee API frame and set the brightness
of an LED accordingly.
*/
const int ledPin = 9;
void setup() {
Serial.begin(9600);
pinMode(ledPin, OUTPUT);
configureRadio(); // check the return value if you need error handling
}
boolean configureRadio() {
// put the radio in command mode:
Serial.flush();
Serial.print("+++");
delay(100);
String ok_response = "OK\r"; // the response we expect.
// Read the text of the response into the response variable
String response = String("");
while (response.length() < ok_response.length()) {
if (Serial.available() > 0) {
response += (char) Serial.read();
}
}
// If we got the right response, configure the radio and return true.
if (response.equals(ok_response)) {
Serial.print("ATAP1\r"); // Enter API mode
delay(100);
Serial.print("ATCN\r"); // back to data mode
return true;
} else {
return false; // This indicates the response was incorrect.
}
}
void loop() {
if (Serial.available() >= 14) { // Wait until we have a mouthful of data
if (Serial.read() == 0x7E) { // Start delimiter of a frame
// Skip over the bytes in the API frame we don't care about
for (int i = 0; i < 10; i++) {
Serial.read();
}
// The next two bytes are the high and low bytes of the sensor reading
int analogHigh = Serial.read();
int analogLow = Serial.read();
int analogValue = analogLow + (analogHigh * 256);
// Scale the brightness to the Arduino PWM range
int brightness = map(analogValue, 0, 1023, 0, 255);
// Light the LED
analogWrite(ledPin, brightness);
}
}
}