ST25DV04K – RF password and factory reset

[michelecapponidaos]

Hello everyone,

I’m currently working with the ST25DV04K chip and I’ve noticed two points that are a bit confusing:

1. There doesn’t seem to be any way to change the RF passwords via I²C.

2. I couldn’t find any command that allows a full factory reset (including resetting the passwords).

My questions are:

• Is this really the case, or am I missing some undocumented/hidden command?

• If the passwords are set via I²C and cannot be changed anymore, doesn’t this risk making the device unusable in case of a configuration mistake?

• Is there any recommended method from ST to bring the chip back to a “clean” state without replacing it?

Thanks in advance to anyone who can clarify these points.

[Brian TIDAL]

Hi,

do you use the ST25DV04K or the ST25DV04KC? ST25DV04K  is Not Recommended for New Design (NRND) whereas ST25DV04KC is active.

Rgds

BT

[JL. Lebon]

Hello,

Let me answer your questions one by one:

"There doesn’t seem to be any way to change the RF passwords via I²C."
-> no there is not. I2C passwords can only be changed from I2C interface and RF passwords can only be changed from RF interface.

"I couldn’t find any command that allows a full factory reset (including resetting the passwords)."
-> there is no such command. Factory reset is not possible.

"Is this really the case, or am I missing some undocumented/hidden command?"
-> your understanding is correct.

"If the passwords are set via I²C and cannot be changed anymore, doesn’t this risk making the device unusable in case of a configuration mistake?"
-> yes, if you forget your password, there is no way to recover or reset it.

"Is there any recommended method from ST to bring the chip back to a “clean” state without replacing it?"
-> If you forgot the password, there is no way to go back to clean state. That would be a serious security breach!

Best regards.