Disable echo

AT command echo interferes with OOB recognition.

Author: Marcus Chang

ESP8266/ESP8266.cpp

@@ -97,6 +97,16 @@ bool ESP8266::at_available()
     return ready;
 }
 
+bool ESP8266::echo_off()
+{
+    _smutex.lock();
+    bool ready = _parser.send("ATE0")
+                 && _parser.recv("OK\n");
+    _smutex.unlock();
+
+    return ready;
+}
+
 struct ESP8266::fw_sdk_version ESP8266::sdk_version()
 {
     int major;

ESP8266/ESP8266.h

@@ -96,6 +96,13 @@ class ESP8266 {
     */
     bool at_available(void);
 
+    /**
+     * Disable echo - required for OOB processing to work
+     *
+     * @return true if echo was successfully disabled
+     */
+    bool echo_off(void);
+
     /**
     * Check sdk version from which firmware is created
     *

ESP8266Interface.cpp

@@ -315,6 +315,9 @@ nsapi_error_t ESP8266Interface::_init(void)
         if (!_esp.reset()) {
             return NSAPI_ERROR_DEVICE_ERROR;
         }
+        if (!_esp.echo_off()) {
+            return NSAPI_ERROR_DEVICE_ERROR;
+        }
         if (!_esp.start_uart_hw_flow_ctrl()) {
             return NSAPI_ERROR_DEVICE_ERROR;
         }