NFCのトピックRe: Why does the TLV Value pattern differ only for MAC addresses?

Why does the TLV Value pattern differ only for MAC addresses?

S_S — Wed, 18 Dec 2024 01:11:52 GMT

Hellow.

We are trying to use NFC TAG to write wifi information written from a smartphone(iOS) to a microcontroller.
When we use TagWriter to write to the NFC TAG 5 Link click and then read it with TagInfo, the size of the MAC address is not what we expected.
Why is this?

The Tag that shows the MAC address is 10 27 and in the case of the photo the Value is FF FF FF FF FF FF FF FF. In this case, Length should be 06, but it is actually 11.

Thank you.

https://www.mikroe.com/ntag-5-link-click

https://apps.apple.com/jp/app/nfc-tagwriter-by-nxp/id1246143221

https://apps.apple.com/jp/app/nfc-taginfo-by-nxp/id1246143596

Re: Why does the TLV Value pattern differ only for MAC addresses?

Fabian_R — Wed, 18 Dec 2024 18:40:14 GMT

Hello sir,

You are correct, the value should be 06

In order to check the full structure of the Wi-Fi NDEF it is required to check the Wi-Fi Alliance's WSC specification.

Regarding the specifics of MAC Address, the ID is 0x10 0x20 (the bytes before the MAC) the values 0x00 0x06.

Could you please let me know if you are able to write the nTtag using an Android smartphone? Is the MAC value correct with Android?

Re: Why does the TLV Value pattern differ only for MAC addresses?

S_S — Thu, 26 Dec 2024 02:21:29 GMT

Hello, Fabian_R.

Upon writing the MAC address from an Android smartphone, I verified that the length of the input was correct.

So do you think there is a problem with the tag writer in the iOS app?

Thank you.