void myService::onDataWritten(const GattCharacteristicWriteCBParams *params)
{
	if(params->charHandle == txChar->getValueAttribute().getHandle()) {
		numBytesReceived = params->len;
		memcpy(receiveBuffer, params->data, numBytesReceived);
		onTxDataWritten(receiveBuffer, numBytesReceived);
	}
}

void myService::onDataSent(unsigned count) 
{
	sent = true;
}

void myService::init()
{
ble.onDataWritten(this, &myService::onDataWritten);	
ble.onDataSent(this, &myService::onDataSent);
}

    /**
     * Setup a callback for the GATT event DATA_SENT.
     */
    void onDataSent(GattServer::ServerEventCallbackWithCount_t callback);

    /**
     * Setup a callback for when a characteristic has its value updated by a
     * client.
     *
     * @Note: it is possible to chain together multiple onDataWritten callbacks
     * (potentially from different modules of an application) to receive updates
     * to characteristics. Many services, such as DFU and UART add their own
     * onDataWritten callbacks behind the scenes to trap interesting events.
     *
     * @Note: it is also possible to setup a callback into a member function of
     * some object.
     */
    void onDataWritten(void (*callback)(const GattCharacteristicWriteCBParams *eventDataP));
    template <typename T> void onDataWritten(T *objPtr, void (T::*memberPtr)(const GattCharacteristicWriteCBParams *context));