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RGrig.1
Visitor II
April 24, 2023
Solved

Why if I set number of characteristics greater than 1 into STM32WB55 BLE service, I can't find the device with ST BLE Toolbox?

  • April 24, 2023
  • 1 reply
  • 733 views

I have a characteristic1 as a write and I want to add a second characteristic as a read, but when I add this second I can't fint the device with the App?

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Best answer by Remy ISSALYS

Hello,

When you add a characteristic to a service, you should increase the value Max_Attribute_Records parameter when you call aci_gatt_add_service function.

The number of attribute records goes from 2 to 5 depending on the characteristic properties:

  • Minimum of 2 (1 for declaration and 1 for the value)
  • Add 1 more record for each additional property: Notify or Indicate, Broadcast, Extended property
    • Notify and Indicate properties correspond to CCCD (Client Characteristic Configuration Descriptor)
    • Broadcast property corresponds to SCCD (Server Characteristic Configuration Descriptor)
    • Extended property corresponds to CEPD (Characteristic Extended Property Descriptor)

Best Regards

1 reply

Remy ISSALYS
Remy ISSALYSBest answer
Technical Moderator
April 26, 2023

Hello,

When you add a characteristic to a service, you should increase the value Max_Attribute_Records parameter when you call aci_gatt_add_service function.

The number of attribute records goes from 2 to 5 depending on the characteristic properties:

  • Minimum of 2 (1 for declaration and 1 for the value)
  • Add 1 more record for each additional property: Notify or Indicate, Broadcast, Extended property
    • Notify and Indicate properties correspond to CCCD (Client Characteristic Configuration Descriptor)
    • Broadcast property corresponds to SCCD (Server Characteristic Configuration Descriptor)
    • Extended property corresponds to CEPD (Characteristic Extended Property Descriptor)

Best Regards