Merge pull request ARMmbed#65 from pan-/fix_led_blinker_instruction

Improve BLE_LEDBlinker example.

BLE_LEDBlinker/readme.md

@@ -6,14 +6,14 @@ The example uses two applications running on two different devices:
 
 1. The first device - the central - runs the application ``BLE_LEDBlinker`` from this repository. This application sends an on/off toggle over BLE.
 
-1. The second device - the peripheral - runs the application [``BLE_LED``](https://github.com/ARMmbed/ble-examples/tree/master/BLE_LED) to respond to the toggle. 
+1. The second device - the peripheral - runs the application [``BLE_LED``](https://github.com/ARMmbed/ble-examples/tree/master/BLE_LED) to respond to the toggle.
 
 	The toggle simply turns the LED on the peripheral device on and off.
 
 # Running the application
 
 ## Requirements
- 
+
 Hardware requirements are in the [main readme](https://github.com/ARMmbed/ble-examples/blob/master/README.md).
 
 This example requires *two* devices.
@@ -22,7 +22,7 @@ This example requires *two* devices.
 
 You will need to build both applications and flash each one to a different board.
 
-Please note: The application ``BLE_LEDBlinker`` in this repository checks a device-specific parameter: ``peerAddr``. Before you build the application, you need to give this parameter the MAC address of your *peripheral* device (the device running the ``BLE_LED`` application).
+Please note: The application ``BLE_LEDBlinker`` in this repository initiate a connection to all ble devices which advertise "LED" as complete local name. By default, the application `BLE_LED` advertise "LED" as complete local name. If you change the local name advertised by the application `BLE_LED` you should reflect your change in this application by changing the value of the constant `PEER_NAME` in `main.cpp`.
 
 **Tip:** You may notice that the application also checks the LED characteristic's UUID; you don't need to change this parameter's value, because it already matches the UUID provided by the second application, ``BLE_LED``.
 
@@ -44,19 +44,18 @@ Building instructions for all mbed OS samples are in the [main readme](https://g
 
 ## Monitoring the application through a serial port
 
-You can run ``BLE_LEDBlinker`` and see that it works properly by monitoring its serial output. 
+You can run ``BLE_LEDBlinker`` and see that it works properly by monitoring its serial output.
 
 You need a terminal program to listen to the output through a serial port. You can download one, for example:
 
 * Tera Term for Windows.
 * CoolTerm for Mac OS X.
 * GNU Screen for Linux.
 
-To see the application's output: 
+To see the application's output:
 
 1. Check which serial port your device is connected to.
-1. Check the baud rate of your device.
-1. Run a terminal program with the correct serial port and baud rate. For example, to use GNU Screen, run: ``screen /dev/tty.usbmodem1412 9600``.
-1. The application should start printing the toggle's value to the terminal. 
+1. Run a terminal program with the correct serial port and set the baud rate to 9600. For example, to use GNU Screen, run: ``screen /dev/tty.usbmodem1412 9600``.
+1. The application should start printing the toggle's value to the terminal.
 
-**Note:** ``BLE_LEDBlinker`` will not run properly if the ``BLE_LED`` application is not running on a second device. The terminal will show a few print statements, but you will not be able to see the application in full operation. 
+**Note:** ``BLE_LEDBlinker`` will not run properly if the ``BLE_LED`` application is not running on a second device. The terminal will show a few print statements, but you will not be able to see the application in full operation.

BLE_LEDBlinker/source/main.cpp

@@ -22,20 +22,41 @@
 DigitalOut alivenessLED(LED1, 1);
 static DiscoveredCharacteristic ledCharacteristic;
 static bool triggerLedCharacteristic;
+static const char PEER_NAME[] = "LED";
 
 void periodicCallback(void) {
     alivenessLED = !alivenessLED; /* Do blinky on LED1 while we're waiting for BLE events */
 }
 
 void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params) {
-    if (params->peerAddr[0] != 0x29) { /* !ALERT! Alter this filter to suit your device. */
-        return;
+    // parse the advertising payload, looking for data type COMPLETE_LOCAL_NAME
+    // The advertising payload is a collection of key/value records where
+    // byte 0: length of the record excluding this byte
+    // byte 1: The key, it is the type of the data
+    // byte [2..N] The value. N is equal to byte0 - 1
+    for (uint8_t i = 0; i < params->advertisingDataLen; ++i) {
+
+        const uint8_t record_length = params->advertisingData[i];
+        if (record_length == 0) {
+            continue;
+        }
+        const uint8_t type = params->advertisingData[i + 1];
+        const uint8_t* value = params->advertisingData + i + 2;
+        const uint8_t value_length = record_length - 1;
+
+        if(type == GapAdvertisingData::COMPLETE_LOCAL_NAME) {
+            if ((value_length == sizeof(PEER_NAME)) && (memcmp(value, PEER_NAME, value_length) == 0)) {
+                printf(
+                    "adv peerAddr[%02x %02x %02x %02x %02x %02x] rssi %d, isScanResponse %u, AdvertisementType %u\r\n",
+                    params->peerAddr[5], params->peerAddr[4], params->peerAddr[3], params->peerAddr[2],
+                    params->peerAddr[1], params->peerAddr[0], params->rssi, params->isScanResponse, params->type
+                );
+                BLE::Instance().gap().connect(params->peerAddr, Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL);
+                break;
+            }
+        }
+        i += record_length;
     }
-    printf("adv peerAddr[%02x %02x %02x %02x %02x %02x] rssi %d, isScanResponse %u, AdvertisementType %u\r\n",
-           params->peerAddr[5], params->peerAddr[4], params->peerAddr[3], params->peerAddr[2], params->peerAddr[1], params->peerAddr[0],
-           params->rssi, params->isScanResponse, params->type);
-
-    BLE::Instance().gap().connect(params->peerAddr, Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL);
 }
 
 void serviceDiscoveryCallback(const DiscoveredService *service) {