Micropython: BLE/ESP32: limit to number of services?

[poesel]

It seems to me that the number of advertised services is limited to three.
This:
self._payload = advertising_payload(name=name, services=([0x1800,0x180F,0x181A,]), appearance=_ADV_APPEARANCE_GENERIC_WEIGHT_SCALE)
works. While this:
self._payload = advertising_payload(name=name, services=([0x1800,0x180F,0x181A,0x181D,]), appearance=_ADV_APPEARANCE_GENERIC_WEIGHT_SCALE)
won't.

Fault message is:
File "main.py", line 100, in _advertise OSError: [Errno 5] EIO MicroPython v1.11-427-gd5cbee3cf-dirty on 2019-10-14; ESP32 module (spiram) with ESP32

I found nothing about a limit in the documentation.
Is this a hardware limit or something that can be configured?

[dpgeorge]

The GAP advertising payload has a limit of 37 bytes (for BLE=4.x) so, depending on the length of name, it's probably just over that limit with more services.

[Cubic-Rambo]

nRF52832 Boards How can it support bluetooth nimble? @dpgeorge

[jimmo]

Yeah, the payload length is the problem here.

I believe the solution here is to use a combination of the BLE_GAP_AD_TYPE_16BIT_SERVICE_UUID_MORE_AVAILABLE (0x02) type, and/or using active scan (via the scan_resp param) to allow more advertising data. I plan to write up an example using this.

[poesel]

Thanks, that was the problem. The name was 8 characters long. Changing this to 1 allowed 4 services to be advertised.

[Walkline80]

Thanks, that was the problem. The name was 8 characters long. Changing this to 1 allowed 4 services to be advertised.

You can also passing "name" param by resp_data
doc link