Hard reset indicator and functionality

* Adding attempts to readLine and state marker if radio module is unresponsive

* Fix spacing around brackets

* Adding attempts to TheTHingsNetwork.h

* No need for else when if has return

* Set default in header file

* decrement attempts

* Proposal to handle exception when RN module does not respond

* Changed variable name from radioModuleInvalidState to needsHardReset

* Added hardReset function with non-blocking delay. made needsHardReset a public variable

* Updating documentation for hardreset

* Changed wording of unresponsive rn module in readline function

* Spacing in if statement in readline function

* Removing comment at readline function

* Fixed spelling mistake of millis in resetHard

* Replacing single qoute with double qoute to fix warning: character constant too long for its type

* remove empty line

* Fixed missing (

* moved adr parameter to reset and added parameter description for hardreset

* Spelling mistake

* Reformulated the non i/o blocking wait function to make it more understandable

* Updated the way while brackets are placed in resetHard

* Updated hardreset documentation to include initial pinmode setup

* rewording of hardreset output pin config

* Using delay(1000) instead of custom delay function to ensure that ESP8266 background operations will work

docs/TheThingsNetwork.md

@@ -28,6 +28,16 @@ void reset(bool adr);
 
 - `bool adr`: Enable/disable Adaptive Data Rate.
 
+## Method: `hardReset`
+
+Performs a hardware reset of the RN module. Input parameter is the pin which the reset pin from the module is connected to. This does clear saved state, e.g. provisioned keys.
+
+```c
+void hardReset(uint8_t resetPin);
+```
+
+- `uint8_t resetPin`: The output pin that is connected to the module's reset pin. The output pin should be configured as output and set to high by the user.
+
 ## Method: `getHardwareEui`
 
 Gets the unique hardware EUI, often used as the DevEUI.

src/TheThingsNetwork.cpp

@@ -357,13 +357,19 @@ void TheThingsNetwork::clearReadBuffer()
   }
 }
 
-size_t TheThingsNetwork::readLine(char *buffer, size_t size)
+size_t TheThingsNetwork::readLine(char *buffer, size_t size, uint8_t attempts)
 {
   size_t read = 0;
-  while (read == 0)
+  while (!read && attempts--)
   {
     read = modemStream->readBytesUntil('\n', buffer, size);
   }
+  if (attempts<=0)
+  { // If attempts is activated return 0 and set RN state marker
+    this->needsHardReset = true; // Inform the application about the radio module is not responsive.
+    debugPrintLn("No response from RN module.");
+    return 0;
+  }
   buffer[read - 1] = '\0'; // set \r to \0
   return read;
 }
@@ -417,7 +423,7 @@ void TheThingsNetwork::reset(bool adr)
   size_t length = readResponse(SYS_TABLE, SYS_RESET, buffer, sizeof(buffer));
 
   autoBaud();
-  length = readResponse(SYS_TABLE, SYS_TABLE, SYS_GET_VER, buffer, sizeof(buffer));  
+  length = readResponse(SYS_TABLE, SYS_TABLE, SYS_GET_VER, buffer, sizeof(buffer));
 
   // buffer contains "RN2xx3[xx] x.x.x ...", splitting model from version
   char *model = strtok(buffer, " ");
@@ -436,6 +442,13 @@ void TheThingsNetwork::reset(bool adr)
     sendMacSet(MAC_ADR, "off");
   }
   this->adr = adr;
+  this->needsHardReset = false;
+}
+
+void TheThingsNetwork::resetHard(uint8_t resetPin){
+  digitalWrite(resetPin, LOW);
+  delay(1000);
+  digitalWrite(resetPin, HIGH);
 }
 
 void TheThingsNetwork::saveState()
@@ -776,8 +789,8 @@ void TheThingsNetwork::configureKR920_923()
 void TheThingsNetwork::configureIN865_867()
 {
   sendMacSet(MAC_ADR, "off"); // TODO: remove when ADR is implemented for this plan
-  sendMacSet(MAC_RX2, "2 866550000"); // SF10  
-  
+  sendMacSet(MAC_RX2, "2 866550000"); // SF10
+
   // Disable the three default LoRaWAN channels
   sendChSet(MAC_CHANNEL_STATUS, 0, "off");
   sendChSet(MAC_CHANNEL_STATUS, 1, "off");
@@ -1035,7 +1048,7 @@ void TheThingsNetwork::sleep(uint32_t mseconds)
 }
 
 void TheThingsNetwork::wake()
-{ 
+{
   autoBaud();
 }
 
@@ -1051,7 +1064,7 @@ void TheThingsNetwork::linkCheck(uint16_t seconds)
   modemStream->write(buffer);
   modemStream->write(SEND_MSG);
   debugPrintLn(buffer);
-  waitForOk();  
+  waitForOk();
 }
 
 uint8_t TheThingsNetwork::getLinkCheckGateways()

src/TheThingsNetwork.h

@@ -61,7 +61,7 @@ class TheThingsNetwork
   void (*messageCallback)(const uint8_t *payload, size_t size, port_t port);
 
   void clearReadBuffer();
-  size_t readLine(char *buffer, size_t size);
+  size_t readLine(char *buffer, size_t size, uint8_t attempts = 3);
   size_t readResponse(uint8_t prefixTable, uint8_t indexTable, uint8_t index, char *buffer, size_t size);
   size_t readResponse(uint8_t table, uint8_t index, char *buffer, size_t size);
 
@@ -88,8 +88,11 @@ class TheThingsNetwork
   void sendGetValue(uint8_t table, uint8_t prefix, uint8_t index);
 
 public:
+  bool needsHardReset = false;
+
   TheThingsNetwork(Stream &modemStream, Stream &debugStream, ttn_fp_t fp, uint8_t sf = TTN_DEFAULT_SF, uint8_t fsb = TTN_DEFAULT_FSB);
   void reset(bool adr = true);
+  void resetHard(uint8_t resetPin);
   void showStatus();
   size_t getHardwareEui(char *buffer, size_t size);
   size_t getAppEui(char *buffer, size_t size);
@@ -106,7 +109,7 @@ class TheThingsNetwork
   void wake();
   void saveState();
   void linkCheck(uint16_t seconds);
-  uint8_t getLinkCheckGateways();  
+  uint8_t getLinkCheckGateways();
   uint8_t getLinkCheckMargin();
 };