Austin Blackstone / Mbed 2 deprecated BLE_EvothingsExample_GATT

This is an mbed side application meant to demonstrate how to create a custom GATT service/characteristic with Evothings.

Dependencies:   BLE_API mbed nRF51822

Intro

This code is meant to be run on an mbed enabled BLE board and paired with the mbed-evothings-customGATT smartphone application.

Details

This code is a demonstration of how to create a custom service (UUID=0xA0000) with two characteristics, a read only characteristic (UUID=0xA001) and a write characteristic (UUID=0xA002). What is written to the write characteristic will be copied across to the read characteristic and broadcast out. If a single byte is written it will be used to toggle the on board LED, if more than 1 byte is written the data will be written out to the terminal. The default max size is 10bytes.

Viewing Data

You can use either the LightBlue app on iOS or the nRF Master Control Panel application on Android to view the advertising data. Alternatively you can use a custom Evothings App to view the data.

Evothings?

Evothings is a rapid prototyping environment that uses cordova to enable you to rapidly develop smartphone applications in Javascript. Please download the Evothings workbench to your computer and the Evothings client to your smartphone. Then grab the code from the github page, drag and drop the index.htm file into Evothings workbench and run it on the Evothings client.

Reference

main.cpp

Committer:
mbedAustin
Date:
2015-03-10
Revision:
10:6acaa9f0ef85
Parent:
9:b33f42191584
Child:
11:b59226338001

File content as of revision 10:6acaa9f0ef85:

#include "mbed.h"
#include "BLEDevice.h"
#include "CustomService.h"

BLEDevice ble;
DigitalOut led(LED1);
uint16_t customServiceUUID  = 0xA000;
uint16_t reachCharUUID      = 0xA001;
uint16_t writeCharUUID      = 0xA002;

const static char     DEVICE_NAME[]        = "ChangeMe!!"; // change this
static const uint16_t uuid16_list[]        = {0xFFFF}; //Custom UUID, FFFF is reserved for development

// Set Up custom Characteristics
static uint8_t readValue[10] = {0};
GattCharacteristic readChar(reachCharUUID, readValue, sizeof(readValue), sizeof(readValue),
                            GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);

static uint8_t writeValue[10] = {0};
GattCharacteristic writeChar(writeCharUUID, writeValue, sizeof(writeValue), sizeof(writeValue),
                             GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);

// Set up custom service
GattCharacteristic *characteristics[] = {&readChar, &writeChar};
GattService        customService(customServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));


/*
 *  Restart advertising when phone app disconnects
*/ 
void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason)
{
    ble.startAdvertising(); 
}

/* 
 *  handle writes to writeCharacteristic
*/
void writeCharCallback(const GattCharacteristicWriteCBParams *params)
{
    // check to see what characteristic was written, by handle
    if(params->charHandle == writeChar.getValueHandle()) {
        // toggle LED if only 1 byte is written
        if(params->len == 1) {
            led = params->data[0];
        }
        // print the data if more than 1 byte is written
        else {
            printf("0x");
            for(int x=0; x < params->len; x++) {
                printf("%x",params->data[x]);
            }
            printf("\n\r"); // print newline
        }
        // update the readChar with the value of writeChar
        ble.updateCharacteristicValue(readChar.getValueHandle(),params->data,params->len);
    }
}

/*
 *  main loop
*/ 
int
main(void)
{
    /* initialize stuff */
    printf("\n\r********* Starting Main Loop *********\n\r");
    ble.init();
    ble.onDisconnection(disconnectionCallback);
    ble.onDataWritten(writeCharCallback);

    /* setup advertising */
    ble.accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE); // BLE only, no classic BT
    ble.setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED); // advertising type
    ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME)); // add name
    ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list)); // UUID's broadcast in advertising packet
    ble.setAdvertisingInterval(160); /* 100ms; in multiples of 0.625ms. */

    // add our custom service
    ble.addService(customService); // Add our custom service to device

    ble.startAdvertising(); // start advertising
    
    // infinite loop waiting for BLE interrupt events
    while (true) {
        ble.waitForEvent(); //Save power
    }
}