TP/SPE/BI-03-C [Client Characteristic Configuration Descriptor Improperly Configured]

[why_do_i_need_a_user_name]

We are trying to complete Bluetooth qualification on our Cycling Power Service (CPS) against the Bluetooth Test Specification (Document Number CPS.TS.1.1.0).

We fail the test case:

TP/SPE/BI-03-C [Client Characteristic Configuration Descriptor Improperly Configured]

• Verify that the IUT responds appropriately when a Client attempts to perform a Cycling Power Control Point procedure with a Client Characteristic Configuration descriptor that is improperly configured.

• Reference [3] 3.4.3

• Initial Condition

• Perform the preamble described in Section 4.2.3.

• Test Procedure

1. A connection is established between the Lower Tester and IUT.
2. The Lower Tester resets to 0 the Client Characteristic Configuration descriptor of the Cycling Power Control Point characteristic.
3. The Lower Tester writes a valid Op Code to the Cycling Power Control Point.
4. Verify the IUT response meets the requirements of the service.

• Expected Outcome
  • Pass verdict
  • The IUT rejects the Write Request by sending an Error Response with an Attribute Protocol Error Code set to Client Characteristic Configuration Descriptor Improperly Configured (0xFD).

I try to send an error response to the tester by calling sd_ble_gatts_hvx().

This call fails with NRF_ERROR_INVALID_STATE because the CCCD is in the wrong state to indicate or notify.

How do I send an error response in this situation?

[Hung Bui]

Hi,

You can't send any notification/indication if the CCCD is not enabled.

In this case you would need to set the authorization permission for write request to 1 (attr_md.wr_auth = 1). With that, the application can wait for the BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST event and select what it should give in the write response code (BLE_GATT_STATUS_ATTERR_CPS_CCCD_CONFIG_ERROR 0x01FD in this case) and call sd_ble_gatts_rw_authorize_reply() to send the write response packet back.

You can have a look at the ble_app_gls to find how we handle BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST event. In your case you would need to check if CCCD is set or not before you send the reply back.

You can have a look at this chart

Without authorization, the softdevice will automatically response with SUCCESS code and update the value of the characteristic.

[why_do_i_need_a_user_name]

excellent tech support thanks