STM32WB: HCI_HARDWARE_ERROR_EVENT (0x02 – BlueCore Time Overrun) Observed on Some Devices

[SatyanarayanOffice]

Hi everyone,

I am encountering a HCI_HARDWARE_ERROR_EVENT with code 0x02 (BlueCore time overrun error) on STM32WB devices.

Key observations:

• Issue is observed only on some units, while others operate normally
• All devices use the same firmware, BLE stack, and FUS versions
• Affected units show unstable BLE behavior (disconnects or degraded performance)

Validation performed:

• Tested with STM32 reference example (BLE_p2pServer)
• The issue is still reproducible
• PCB layout and hardware design have been reviewed and validated
• No application-specific changes involved during testing

Questions:

1. Root cause
   • What typically triggers a BlueCore time overrun at the controller level?
   • Does this point more toward hardware timing issues (clock accuracy, RF timing), or internal controller or stack conditions?
2. Unit variation
   • Has anyone observed this error occurring only on a subset of devices?
   • Could this be related to component tolerances (HSE or LSE oscillator, RF matching network, power stability, etc.)?
3. Failure diagnosis
   • What is the best way to identify the source of this issue?
   • Any recommended approach to isolate whether it is:
     • Clock-related
     • Power-related
     • RF-related
     • etc.
4. Mitigation or fixes
   • Are there improvements in newer BLE stack or FUS versions related to this?
   • Any configuration or system-level practices to avoid timing overruns?

Summary:

• Reproducible under reference BLE application
• Design and layout validated
• Observed only on some hardware units
• Likely related to device-specific or marginal conditions

Please let me know if any additional details, logs, or configuration information are required.

Any insights or similar experiences would be greatly appreciated.

Thanks!

[SatyanarayanOffice · Accepted solution]

Hi ST Support Team,

We are no longer observing the hardware time overrun errors after upgrading the BLE Stack and FUS from Stack v1.11.0 / FUS v1.2.0 to Stack v1.24.0 / FUS v2.2.0.

Could you please share any relevant references, such as release notes, known issue fixes, or change logs, indicating whether this issue was addressed as part of the BLE stack/FUS updates?

Regards,
Satyanarayan

[Joe_]

Hi,

Thanks for your feedback.

Since you were using a very old BLE Stack / FUS version, it is quite likely that this issue has been fixed or improved in one of the later releases. Please have a look at the BLE Stack and FUS release notes, as they list the bug fixes, known issues, and improvements introduced over time.

Best regards,
Joé