embedded system_error ai_generated partial

RTC: Tamper event detected on TAMP2, backup registers cleared, system must reinitialize

ID: embedded/rtc-tamper-battery-backed

Also available as: JSON · Markdown · 中文
80%Fix Rate
84%Confidence
1Evidence
2025-01-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
STM32L4 series active — — —
STM32CubeMX v6.9.0 active — — —
HAL_RTC v2.3.0 active — — —

Root Cause

A tamper detection event on the RTC TAMP2 pin triggered automatic clearing of backup registers (BKP) to protect sensitive data, requiring full system reinitialization.

generic

中文

RTC TAMP2引脚上的篡改检测事件触发了自动清除备份寄存器（BKP）以保护敏感数据，需要完全重新初始化系统。

Official Documentation

https://www.st.com/resource/en/application_note/an4650-rtc-tamper-and-timestamp-features-in-stm32-microcontrollers-stmicroelectronics.pdf

Workarounds

  1. 85% success Implement a debounce filter on the TAMP2 pin using a low-pass RC circuit (e.g., 10kΩ resistor + 100nF capacitor) to filter out transient glitches. 
    Implement a debounce filter on the TAMP2 pin using a low-pass RC circuit (e.g., 10kΩ resistor + 100nF capacitor) to filter out transient glitches.
  2. 75% success After tamper detection, restore backup registers from a secure non-volatile store (e.g., external EEPROM or flash) if the tamper was false. 
    After tamper detection, restore backup registers from a secure non-volatile store (e.g., external EEPROM or flash) if the tamper was false.

中文步骤

  1. Implement a debounce filter on the TAMP2 pin using a low-pass RC circuit (e.g., 10kΩ resistor + 100nF capacitor) to filter out transient glitches.
  2. After tamper detection, restore backup registers from a secure non-volatile store (e.g., external EEPROM or flash) if the tamper was false.

Dead Ends

Common approaches that don't work:

  1. Disable the tamper detection feature entirely 70% fail

    Removes security protection; may be unacceptable for applications requiring anti-tamper (e.g., metering, secure boot).

  2. Short-circuit TAMP2 pin to ground to prevent false triggers 90% fail

    Damages the pin or causes short circuit; does not address the root cause of noise or mechanical tamper.

  3. Reinitialize backup registers without checking tamper flag 80% fail

    Overwrites valid data and masks the tamper event, potentially allowing unauthorized access to persist.