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:
- 2015-04-02
- Revision:
- 17:dfe796bba97c
- Parent:
- 16:feee85aefb34
File content as of revision 17:dfe796bba97c:
#include "mbed.h" #include "BLEDevice.h" BLEDevice ble; DigitalOut led(LED1); uint16_t customServiceUUID = 0xA000; uint16_t readCharUUID = 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}; ReadOnlyArrayGattCharacteristic<uint8_t, sizeof(readValue)> readChar(readCharUUID, readValue); static uint8_t writeValue[10] = {0}; WriteOnlyArrayGattCharacteristic<uint8_t, sizeof(writeValue)> writeChar(writeCharUUID, writeValue); // 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]; (params->data[0] == 0x00) ? printf("\n\rled on ") : printf("\n\rled off "); // print led toggle } // print the data if more than 1 byte is written else { printf("\n\r Data received: length = %d, data = 0x",params->len); for(int x=0; x < params->len; x++) { printf("%x",params->data[x]); } } // 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(100); // 100ms. // add our custom service ble.addService(customService); // start advertising ble.startAdvertising(); // infinite loop waiting for BLE interrupt events while (true) { ble.waitForEvent(); //Save power } }