Is there a way to add more than 5 BLE characteristics per service

[nollstead]

Hello, I'm configuring an STM32WB55CEU6 in STM32CubeIDE and am setting up the BLE part now and I noticed that the IDE only let's me setup 5 characteristics per service.  In my application (a remote control) I need about 15 characteristics.  Is there a way to increase that number?    

[_Joe_ · Accepted solution]

Hi Nollstead,
With STM32WB, it is not possible to add more than 5 characteristics  per service using STM32CubeMX. The solution would be to add the other characteristic manually without using STM32CubeMX.
This limitation has been improved on STM32WBA, with a maximum of 25 characteristics  per service.

BR, Joé

[nollstead]

Thank you for your answer, I suspected that was the case and this explains why I saw references to 25 in a few places.  Right now since I'm an STM32 newbie I'd like to stick to STM32CubeIDE so it'd probably work to spread those across three services so I'll try that.

[_Joe_]

Yes, it would seem to be a good solution to keep your project compatible with the Cube ecosystem.

BR, Joé

[jeffl.kelley9]

Would adding them manually be making calls to aci_gatt_add_char ?

It ends up with an out-of-memory error 0x98 and changing CFG_BLE_NUM_GATT_ATTRIBUTES does not seem to help.  Obviously I need to learn how to do this, what resources are available?

[jeffl.kelley9]

For future viewers:  aci_gatt_add_service() has a parameter which defines space for attributes.