(support) Cannot write to BLE characteristic with vector

[MaxMyzer]

System: ESP32 C3
ArduinoBLE 1.3.7

I have a system where I would like to write and read from another device. I am currently using nRF Connect to test functionality.

When I check if I canWrite, it always returns false - if I do anyway, it only seems to work for a 0 value.

I have created a sketch to demonstrate my issue:

#include <Arduino.h>
#include <ArduinoBLE.h>
#include <float16.h>
#include <vector>
void setup() {
  Serial.begin(115200);  // [DEBUG] start serial w/ Baud 115200
  while (!Serial.available())
    ;  // [DEBUG] wait for serial to connect...

  Serial.println("Initializing BLE service");
  BLEService* service = new BLEService("1810");
  BLETypedCharacteristic<std::vector<char>>* characteristic = new BLETypedCharacteristic<std::vector<char>>("2A35", BLERead | BLENotify | BLEIndicate | BLEWriteWithoutResponse | BLEWrite);
  BLEDescriptor* descriptor = new BLEDescriptor("2901", "test_descriptor");
  BLELocalDevice* device = new BLELocalDevice();
  if (device->begin()) Serial.println("BLE device started");
  else Serial.println("BLE device failed to start");
  if (device->setLocalName("test_name")) Serial.println("BLE name set");
  else Serial.println("BLE name failed to set");
  device->setDeviceName("test_name");
  if (device->setAdvertisedService(*service)) Serial.println("BLE service advertised");
  else Serial.println("BLE service failed to advertise");
  device->setEventHandler(BLEConnected, ([](BLEDevice central) {
                            Serial.printf("Connected to %s\n", central.address().c_str());
                          }));
  device->setEventHandler(BLEDisconnected, ([](BLEDevice central) {
                            Serial.println("Disconnected");
                          }));
  characteristic->addDescriptor(*descriptor);
  service->addCharacteristic(*characteristic);
  device->addService(*service);
  device->advertise();

  Serial.println("BLE service started");
  Serial.println("trying to write:");
  std::vector<char> data = { 0x04, 0x50, 0x54, (char)0x90, 0x5E, 0x40, 0x4D, 0x00, 0x55 };
  if (characteristic->canWrite()) characteristic->writeValue(data);
  else Serial.println("Cannot write to characteristic");


  Serial.print("done");
  exit(0);
}
void loop() {}

I am not quite sure what it is I am doing wrong, any help would be appreciated.

[MaxMyzer]

A quick update, with a string, I can actually write, but canWrite still returns false

[per1234]

Hi @MaxMyzer. Thanks for your interest in this open source project. This issue tracker is only to be used to report bugs or feature requests specific to the project. This topic is more appropriate for the Arduino Forum. I'm sure we will be able to help you out over there:

https://forum.arduino.cc/

[MaxMyzer]

I have created a forum topic (in case anyone else has this issue) here