Added error check on WriteCan example (#36)

- Added error check on WriteCan example
- Modified Digital_output example in order to call or setLatch or setRetry

Author: Rocketct

examples/CAN/WriteCan/WriteCan.ino

@@ -45,6 +45,10 @@ void loop() {
   mbed::CANMessage msg = mbed::CANMessage(13ul, &payload, payload_size);
   if (comm_protocols.can.write(msg)) {
     Serial.println("Message sent");
+  } else {
+    Serial.println("Transmission Error: ");
+    Serial.println(comm_protocols.can.tderror());
+    comm_protocols.can.reset();
   }
 
   delay(100);

examples/Digital_output/Digital_output.ino

@@ -39,13 +39,15 @@ using namespace automation;
 
 void setup() {
   Serial.begin(9600);
-  //The loop starts only when the serial monitor is opened.
+  // The loop starts only when the serial monitor is opened.
   while (!Serial);
 
   //Set over current behavior of all channels to latch mode:
   digital_programmables.setLatch();
-  //Set over current behavior of all channels to auto retry mode:
-  digital_programmables.setRetry();
+
+  // Uncomment this line to set over current behavior of all
+  // channels to auto retry mode instead of latch mode:
+  // digital_programmables.setRetry();
 
   //At startup set all channels to OPEN
   digital_outputs.setAll(0);
@@ -55,17 +57,17 @@ void setup() {
 void loop() {
   Serial.println("DIGITAL OUT:");
 
-  //Set all channels to CLOSED
+  // Set all channels to CLOSED
   digital_outputs.setAll(255);
   Serial.print("All channels are CLOSED for 1s...");
   delay(1000);
 
-  //Set all channels to OPEN
+  // Set all channels to OPEN
   digital_outputs.setAll(0);
   Serial.println("now they are OPEN.");
   delay(1000);
 
-  //Toggle each channel for 1s, one by one
+  // Toggle each channel for 1s, one by one
 
   digital_outputs.set(0, HIGH);
   Serial.print("CH0 is CLOSED for 1s...");