Add basic I2C bus testing at startup

Author: nseidle

Firmware/RTK_Surveyor/Begin.ino

@@ -476,8 +476,8 @@ void beginGNSS()
 //Configuration can take >1s so configure during splash
 void configureGNSS()
 {
-  if(online.gnss == false) return;
-  
+  if (online.gnss == false) return;
+
   i2cGNSS.setAutoPVTcallbackPtr(&storePVTdata); // Enable automatic NAV PVT messages with callback to storePVTdata
   i2cGNSS.setAutoHPPOSLLHcallbackPtr(&storeHPdata); // Enable automatic NAV HPPOSLLH messages with callback to storeHPdata
 
@@ -811,3 +811,24 @@ void beginIdleTasks()
         index); //Core where task should run, 0=core, 1=Arduino
   }
 }
+
+void beginI2C()
+{
+  Wire.begin(); //Start I2C on core 1
+  //Wire.setClock(400000);
+
+  //begin/end wire transmission to see if bus is responding correctly
+  //All good: 0ms, response 2
+  //SDA/SCL shorted: 1000ms timeout, response 5
+  //SCL/VCC shorted: 14ms, response 5
+  //SCL/GND shorted: 1000ms, response 5
+  //SDA/VCC shorted: 1000ms, reponse 5
+  //SDA/GND shorted: 14ms, response 5
+  unsigned long startTime = millis();
+  Wire.beginTransmission(0x15); //Dummy address
+  int endValue = Wire.endTransmission();
+  if (endValue == 2)
+    online.i2c = true;
+  else
+    Serial.println("Error: I2C Bus Not Responding");
+}

Firmware/RTK_Surveyor/RTK_Surveyor.ino

@@ -511,8 +511,7 @@ void setup()
 
   beginIdleTasks();
 
-  Wire.begin(); //Start I2C on core 1
-  //Wire.setClock(400000);
+  beginI2C(); 
 
   beginDisplay(); //Start display first to be able to display any errors
 

Firmware/RTK_Surveyor/menuSystem.ino

@@ -8,6 +8,10 @@ void menuSystem()
     Serial.println();
     Serial.println("Menu: System Menu");
 
+    beginI2C();
+    if (online.i2c == false)
+      Serial.println("I2C: Offline - Something is causing bus problems");
+
     Serial.print("GNSS: ");
     if (online.gnss == true)
     {

Firmware/RTK_Surveyor/settings.h

@@ -452,4 +452,5 @@ struct struct_online {
   bool txNtripDataCasting = false;
   bool lband = false;
   bool lbandCorrections = false;
+  bool i2c = false;
 } online;