USB Debugging Tutorial (#1162)

* Checkpoint

- Work in progress

* Checkpoint

- Serial tutorial

* Checkpoint

- Device lookup

* Checkpoint

- Device ID and ICCID lookup functions

* Checkpoint

- Work in progress before refactoring listening mode support

* Checkpoint

- Code cleanup
[ci skip]

* USB Serial Debug Tutorial

Author: rickkas7

src/assets/files/UsbSerialSimple.cpp

@@ -0,0 +1,31 @@
+#include "Particle.h"
+
+SerialLogHandler logHandler;
+
+SYSTEM_THREAD(ENABLED);
+
+const std::chrono::milliseconds logPeriod = 5s;
+unsigned long lastLog;
+int counter;
+
+void setup()
+{
+}
+
+void loop()
+{
+    if (Network.listening())
+    {
+        // If we are in listening mode (blinking dark blue), don't
+        // output by USB serial, because it can conflict with
+        // serial commands.
+        return;
+    }
+
+    if (millis() - lastLog >= logPeriod.count())
+    {
+        lastLog = millis();
+
+        Log.info("counter=%d", ++counter);
+    }
+}

src/assets/files/UsbSerialTwoWay.cpp

@@ -0,0 +1,56 @@
+#include "Particle.h"
+
+SerialLogHandler logHandler;
+
+SYSTEM_THREAD(ENABLED);
+
+const std::chrono::milliseconds logPeriod = 5s;
+unsigned long lastLog;
+int counter;
+
+const size_t BUF_SIZE = 128;
+char buf[BUF_SIZE];
+size_t bufOffset = 0;
+
+void setup()
+{
+}
+
+void loop()
+{
+    if (Network.listening())
+    {
+        // If we are in listening mode (blinking dark blue), don't
+        // output by USB serial, because it can conflict with
+        // serial commands.
+        return;
+    }
+
+    if (millis() - lastLog >= logPeriod.count())
+    {
+        lastLog = millis();
+
+        Log.info("counter=%d", ++counter);
+    }
+
+    while (Serial.available())
+    {
+        char c = (char)Serial.read();
+        if (c == '\r' || c == '\n')
+        {
+            if (bufOffset > 0)
+            {
+                buf[bufOffset] = 0;
+                Log.info("received %s", buf);
+            }
+            bufOffset = 0;
+        }
+        else
+        {
+            if ((bufOffset + 1) < (BUF_SIZE - 1))
+            {
+                buf[bufOffset++] = c;
+            }
+        }
+    }
+}