Doc. No: Unex-QSG-21-003
20/23
A printed version of this document is an uncontrolled copy
© 2021 Unex Technology Corporation – Company Confidential
9.9.1.
Production Mode
In production mode, the SOM-301(v2)/SOM-351 will erase the CSP (critical security
parameter) material saved in eHSM. The eHSM hardware will be left unusable because the
CSP cannot be rewritten to the chip anymore. Two additional tamper modes are available
when entering production mode: normal mode and standby mode.
9.9.1.1.
Normal Mode
Tamper response provides protection against tamper attempts during operational state
when the chip is powered on. When it is enabled, tamper event will immediately trigger the
zeroization sequence. Enabling this mode is done by invoking the Enable Normal mode
tamper response service API.
9.9.1.2.
Standby Mode
Tamper response provides protection against tamper attempts while the chip is in sleep
mode state. When it is enabled, any previously latched tamper event during sleep mode
will trigger the zeroization sequence upon power-up. Enabling this mode is done by
invoking the Enable standby mode tamper response service API.
9.9.2.
Test Mode
In test mode, the SOM-301(v2)/SOM-351 will not erase the CSP (critical security
parameter) material saved in eHSM. Each invocation of the tamper signal increments an
internal counter within the eHSM. This counter can then be inquired by calling the eHSM
runtime status API, providing evidence for the tamper signal detection.
9.10.
Thermal Management
If performing heavy V2X transmission on SOM-301(v2)/SOM-351, it is recommended
to add thermal vias and expose bare copper top layer on the system board to help disperse
heat. Inserting a soft silicone thermally conductive pad between the system board and
SOM-301(v2)/SOM-351 could facilitate heat dispersion to the system board more efficiently.
