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Associate III
January 26, 2024
Solved

ST25TV

  • January 26, 2024
  • 4 replies
  • 2333 views

Hi,

I want to know if there is a provision to lock an entire area in ST25TV tags. I can see from the datasheet that blocks 0 and 1 can be locked, but I cannot see anything for other blocks. I know that I can use a password to do same but I do not want to use passwords. Basically, I want to write to an area in the tag and make it non-editable forever. Is this possible ?

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Best answer by JL. Lebon

Hello,

For the ST25TV16K and ST25TV64K, it is not possible to lock more blocks than block 0 and 1.
Nevertheless, it is possible to do what you want to do, which is locking all the blocks permanently using the password mechanism.

If you look at the RFA1SS, RFA2SS etc. and in particular at fields PWD_CTRL_Ax, you can see that value 00b in this filed means: "RF user security session can't be opened by a password". If you combine this with field RW_PROTECTION_Ax=01b (write protection), it means that the corresponding memory area will be protected against write and there will be no way to unprotect it using a password. So, the write protection is permanent, which looks like what you are willing to do.

Off course, someone who knows the configuration password can still change those settings. If you don't want this to happen, you can lock the configuration (LOCK_CFG configuration byte).

Best regards.

4 replies

JL. Lebon
ST Employee
January 26, 2024

Hello, 

It depends on what version (memory size) of ST25TV you are using. Is it ST25TV16K, ST25TV64K or ST25TV512, ST25TV02K ?

Best regards.

Luke_abcAuthor
Associate III
January 26, 2024

It is for ST25TV16K and ST25TV64K. Is it possible for these series ?

JL. Lebon
JL. LebonBest answer
ST Employee
January 26, 2024

Hello,

For the ST25TV16K and ST25TV64K, it is not possible to lock more blocks than block 0 and 1.
Nevertheless, it is possible to do what you want to do, which is locking all the blocks permanently using the password mechanism.

If you look at the RFA1SS, RFA2SS etc. and in particular at fields PWD_CTRL_Ax, you can see that value 00b in this filed means: "RF user security session can't be opened by a password". If you combine this with field RW_PROTECTION_Ax=01b (write protection), it means that the corresponding memory area will be protected against write and there will be no way to unprotect it using a password. So, the write protection is permanent, which looks like what you are willing to do.

Off course, someone who knows the configuration password can still change those settings. If you don't want this to happen, you can lock the configuration (LOCK_CFG configuration byte).

Best regards.

Luke_abcAuthor
Associate III
January 26, 2024

Hi @JL. Lebon , 

Than you for your reply. Is it possole to kill the tag if LOCK_CFG =1 ?

JL. Lebon
ST Employee
January 26, 2024

Hello, 

No it is no more possible once LOCK_CFG=1.

Best regards.