Added KISS flow control

Config.h

@@ -26,6 +26,9 @@
 		const int pin_dio = 2;
 		const int pin_led_rx = 5;
 		const int pin_led_tx = 4;
+
+		#define FLOW_CONTROL_ENABLED true
+		#define QUEUE_SIZE 0
 	#endif
 
 	#if MCU_VARIANT == MCU_1284P
@@ -34,6 +37,9 @@
 		const int pin_dio = 2;
 		const int pin_led_rx = 12;
 		const int pin_led_tx = 13;
+
+		#define FLOW_CONTROL_ENABLED true
+		#define QUEUE_SIZE 24
 	#endif
 
 	// MCU independent configuration parameters
@@ -42,6 +48,7 @@
 
 	// Default LoRa settings
 	int  lora_sf   = 0;
+	int  lora_cr   = 5;
 	int  lora_txp  = 0xFF;
 	uint32_t lora_bw   = 0;
 	uint32_t lora_freq = 0;

Framing.h

@@ -14,6 +14,7 @@
 	#define CMD_SF			0x04
 	#define CMD_RADIO_STATE 0x05
 	#define CMD_RADIO_LOCK	0x06
+	#define CMD_READY		0x0F
 
 	#define CMD_STAT_RX		0x21
 	#define CMD_STAT_TX		0x22

RNode_Firmware.ino

@@ -42,6 +42,7 @@ bool startRadio() {
         setTXPower();
         setBandwidth();
         setSpreadingFactor();
+        setCodingRate();
         getFrequency();
 
         LoRa.enableCrc();
@@ -178,6 +179,10 @@ void transmit(size_t size) {
     LoRa.endPacket();
     led_tx_off();
     LoRa.receive();
+
+    if (FLOW_CONTROL_ENABLED)
+      kiss_indicate_ready();
+
   } else {
     kiss_indicate_error(ERROR_TXFAILED);
     led_indicate_error(5);

Utilities.cpp

@@ -146,6 +146,13 @@ void kiss_indicate_random(uint8_t byte) {
 	Serial.write(FEND);
 }
 
+void kiss_indicate_ready() {
+	Serial.write(FEND);
+	Serial.write(CMD_READY);
+	Serial.write(0x01);
+	Serial.write(FEND);
+}
+
 bool isSplitPacket(uint8_t header) {
 	return (header & FLAG_SPLIT);
 }
@@ -165,6 +172,10 @@ void setSpreadingFactor() {
 	if (radio_online) LoRa.setSpreadingFactor(lora_sf);
 }
 
+void setCodingRate() {
+	if (radio_online) LoRa.setCodingRate4(lora_cr);
+}
+
 void setTXPower() {
 	if (radio_online) LoRa.setTxPower(lora_txp);
 }