SLUSCT1B June 2017 – January 2019 TPS53681
PRODUCTION DATA.
The MFR_SPECIFIC_42 command can be optionally used to set a password for NVM programming. To prevent a hacker from simply sending the password command with all possible passwords, the TPS53681 goes into a special extra-secure state when an incorrect password is received. In this state, all passwords are rejected, even the valid one. The device must be power cycled to clear this state so that another password attempt may be made. When NVM security is enabled, the TPS53681 will not accept writes to any command other than PAGE and PHASE, which are necessary for reading certain parameters.
Enabling NVM Security
Disabling NVM Security
To disable NVM security, use the following procedure:
NVM security will be re-enabled at the next power-on, unless MFR_SPECIFIC_42 is set to FFFFh (NVM Security Disabled), and an NVM store operation (issue STORE_DEFAULT_ALL and wait 100 ms) is performed.
Determining Whether NVM Security is Active
Reads to the MFR_SPECIFIC_42 command returns one of three values: