Johan Westlund

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8 years, 6 months ago.

Send a double array using ReadOnlyGattCharacteristic

I'm trying to send an array of double values over BLE

BLEService.h

...
class BLEService {

public:
  BLEService(BLEDevice &_ble);
  ~BLEService();
  void setupService();
  void sendData(uint8_t* payload, uint16_t len);

private:

  BLEDevice &ble;

  double* Buffer;

  ReadOnlyGattCharacteristic<double, 32> data;
  GattService* BLEService;

...

BLEService.c

#include "BLEService.h"
BLEService::BLEService(BLEDevice &_ble) : ble(_ble)
{	
	Buffer = new double [32]();
	
	setupService();
}

void BLEService::setupService() {

    const uint8_t SERVICE_UUID[16] = ...
    const uint8_t DATA_UUID[16] = ...
    UUID serviceUUID(SERVICE_UUID);
    UUID dataUUID(DATA_UUID);

    data(dataUUID, Buffer, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);

    GattCharacteristic *charTable[] = {&data};
    BLEService = new GattService(serviceUUID, charTable, sizeof(charTable) / sizeof(GattCharacteristic*));
    ble.addService(*BLEService );
    serviceAdded = true;
}

void BLEService::sendData(uint8_t* payload, uint16_t len)
{
    memcpy(Buffer, payload, len);
    ble.updateCharacteristicValue(data.getValueHandle(), (uint8_t*)Buffer, len);
}

The first problem is that gcc4mbed gives me an "does not name a type" error for ReadOnlyGattCharacteristic<double, 32>. Not sure I'm using it the correct way.

I'm sure that there is other errors as well as I'm pretty new to C++.

Update: Discovered that I have used an old BLE_API library that didn't include ReadOnly. Now it compiles with:

GattCharacteristic(dataUUID, reinterpret_cast<uint8_t *>(Buffer), sizeof(double) * 32, sizeof(double) * 32,	GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY | GattCharacteristic::BLE_GATT_FORMAT_FLOAT64);

My library didn't have the function for it.

posted by Johan Westlund 14 Jul 2017
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