Irreversible security-related features and settings in TRAVEO™ T2G MCU
Japanese Translation: TRAVEO™ T2G MCUの不可逆なセキュリティ機能や設定
There are some security-related features and settings that, once set, cannot be restored using the debugger in TRAVEO™ T2G MCU.
The following is a main list of irreversible security functions and settings.
It is recommended that you prepare spare chips or socket board since the chip may become inaccessible during security evaluation.
Once written, this memory cannot be changed anymore.
・Supervisory Flash (SFlash)
If Lifecycle stage is changed to SECURE or SECURE_W_DEBUG, modification is restricted by SECURE_HASH.
・Lifecycle stage setting
Lifecycle stage settings such as NORMAL_PROVISIONED, SECURE and RMA are written to eFuse and cannot be reverted.
・Normal Access Restriction (NAR)/Normal Dead Access Restriction (NDAR) of SFlash
When the device is in NORMAL_PROVISIONED, the SFlash NAR/NDAR settings can be changed, but the restrictions cannot be relaxed. For example, the disable DAP setting cannot be changed to the enable DAP setting.
・Protection Unit (MPU, SMPU, PPU) Settings
If the Protection Unit setting is set to prohibit external debugger access and no mechanism is in place to allow access, the debugger will not be able to connect.
・Flash Write Protection Unit (FWPU) setting of SFlash
When FWPU is set for SFlash by SWPU, the SWPU settings are stored in SFlash and cannot be rewritten.
- TRAVEO™ T2G Architecture TRM
- AN228680 Secure system configuration in TRAVEO™ T2G family
More like this (optional)
This KBA applies to the following series of TRAVEO™ T2G MCUs:
- TRAVEO™ T2G CYT2xx series
- TRAVEO™ T2G CYT3xx series
- TRAVEO™ T2G CYT4xx series