What is the difference between static lock bytes and dynamic lock byte

[zhaoyuzhang]

Hi,

Taking NTAG 216 for example, I understood that static lock bytes are OTP bytes. While, for dynamic lock bytes, through my experiment, I found  that  I cannot change them back to 0 either. But this is not mentioned in the spec  http://www.nxp.com/documents/data_sheet/NTAG213_215_216.pdf .  So just wanted to confirm:

1. Are dynamic lock bytes also OTP bytes? Or is there a way to change them back to 0 once they are set to 1?

2. If dynamic lock bytes also OTP bytes, then what is the difference between static and dynamic lock bytes except that they lock different address. Basically I don't understand the meaning of  'static' and 'dynamic'.

Thanks!

[Jorge_Gonzalez · Accepted solution]

Hello Zhaoyu Zhang:

The setting of the dynamic lock bytes is also irreversible, so you can set the bits to 1 but not back to 0. The difference between "static" and "dynamic" is the position in memory for such bits:

- Static lock bytes are always the bytes 2 and 3 in page 2 of the NTAG memory:

- Dynamic lock bytes can be at different positions in memory. For example for NTAG213/215/216 you find the dynamic lock bytes at pages 40/130/226:

This naming is based on the NFC Forum Type 2 Tag Technical Specification.

I hope this clarifies.

Best Regards!

Jorge Gonzalez

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[zhaoyuzhang]

Hi Jorge,

Sorry for late reply and thanks a lot for the detailed clarification! This is really helpful!

Thanks,

Zhaoyu