Add tools

tools/AT_Debug/AT_Debug.ino

@@ -0,0 +1,36 @@
+/**************************************************************
+ *
+ * To run this tool, you need to install StreamDebugger library:
+ *   https://github.com/vshymanskyy/StreamDebugger
+ *
+ **************************************************************/
+
+#include <TinyGsmClient.h>
+#include <StreamDebugger.h>
+
+char apn[]  = "YourAPN";
+char user[] = "";
+char pass[] = "";
+
+StreamDebugger GsmSerial(Serial1, Serial);
+GsmClient gsm(GsmSerial);
+
+void setup() {
+  // Set console baud rate
+  Serial.begin(115200);
+  delay(10);
+
+  // Set GSM module baud rate
+  GsmSerial.begin(115200);
+  delay(3000);
+
+  gsm.networkConnect(apn, user, pass);
+
+  // Access AT commands from Serial
+  GsmSerial.directAccess();
+}
+
+void loop() {
+
+}
+