Added AFSK via OOK example

examples/AFSK/AFSK_Tone_AM/AFSK_Tone_AM.ino

@@ -0,0 +1,101 @@
+/*
+   RadioLib AM-modulated AFSK Example
+
+   This example shows hot to send AM-modulated
+   audio FSK tones using SX1278's OOK modem.
+
+   Other modules that can be used for AFSK:
+    - SX127x/RFM9x
+    - RF69
+    - SX1231
+    - CC1101
+
+   For default module settings, see the wiki page
+   https://github.com/jgromes/RadioLib/wiki/Default-configuration
+
+   For full API reference, see the GitHub Pages
+   https://jgromes.github.io/RadioLib/
+*/
+
+// include the library
+#include <RadioLib.h>
+
+// SX1278 has the following connections:
+// NSS pin:   10
+// DIO0 pin:  2
+// RESET pin: 9
+SX1278 radio = new Module(10, 2, 9);
+
+// create AFSK client instance using the FSK module
+// this requires connection to the module direct
+// input pin, here connected to Arduino pin 5
+// SX127x/RFM9x:  DIO2
+// RF69:          DIO2
+// SX1231:        DIO2
+// CC1101:        GDO2
+AFSKClient audio(&radio, 5);
+
+void setup() {
+  Serial.begin(9600);
+
+  // initialize SX1278 with default settings
+  Serial.print(F("[SX1278] Initializing ... "));
+  int state = radio.beginFSK();
+
+  // when using one of the non-LoRa modules for AFSK
+  // (RF69, CC1101, Si4432 etc.), use the basic begin() method
+  // int state = radio.begin();
+
+  if(state == ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+
+  // initialize AFSK client
+  Serial.print(F("[AFSK] Initializing ... "));
+  state = audio.begin();
+  if(state == ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+
+  // after that, set mode to OOK
+  Serial.print(F("[SX1278] Switching to OOK ... "));
+  state = radio.setOOK(true);
+  if(state == ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+}
+
+void loop() {
+  // AFSKClient can be used to transmit tones,
+  // same as Arduino tone() function
+
+  // 400 Hz tone
+  Serial.print(F("[AFSK] 400 Hz tone ... "));
+  audio.tone(400);
+  delay(1000);
+
+  // silence
+  Serial.println(F("done!"));
+  audio.noTone();
+  delay(1000);
+
+  // AFSKClient can also be used to transmit HAM-friendly
+  // RTTY, Morse code, Hellschreiber, SSTV and AX.25.
+  // Details on how to use AFSK are in the example
+  // folders for each of the above modes.
+
+  // CAUTION: Unlike standard AFSK, the result when using OOK
+  // must be demodulated as AM!
+}