Value in Monotonic counter can be kept persistently after power down?

[JasonC007]

I am thinking to use the monotonic counter in imx8mm to keep the value only increased.

But it seems the counter value will be reset when there is power down.

Is there someone have tried to keep the value after power reset?

Or if someone saw the information how-to, please share with me.

[JasonC007]

I understand there is no way to keep the value if there is no backup battery connected. Am I understanding correctly?

[JosephAtNXP]

Correct.

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

Please see:

Low-Power Section of SNVS (SNVS_LP)

The SNVS_LP section provides hardware that enables secure storage and protection of sensitive data. The SNVS module is designed to safely hold security-related data such as cryptographic key, time counter, monotonic counter, and general purpose security information.

When the LP section is powered by an uninterrupted power supply, like a backup battery, the state of these registers is maintained even when the main chip power is off. (see SNVS power domains)

You can keep the counter from being restarted as long as the PMIC is not in OFF mode. According to PCA9450 datasheet.

Regards