mfrc522 reading some tags but not others

[petercwallis]

Hello all,

we have a nfc reader hooked up to a raspberry pi and can read and write to three different types of NTAG213 as required, but a fourth type does not even register as present.  I would think this fourth type is broken, but I can dump the data from it using an app on the phone and it all looks fine.  Any suggestions about what might be wrong with our set-up?

Dissecting the tag-type that does not work, there is an antenna board with RN1218_50p on it.

I have fiddled with the power and sensitivity to no avail..

[petercwallis]

We still can't figure out how to debug the MFRC522 and these mystery tags.  Why would the phone be able to read them but not the mfrc522 when the mfrc522 can read all the other tags?

Time to get a different type of tag reader perhaps?

[petercwallis]

Does anyone know why the Taginfo app might work with a particular type of NTAG213 but the MFC522 tag reader does not even detect the tag?

[fangfang]

Hello @petercwallis .

The fourth type is also NTAG213? And can you read or writer NTAG213 via Taginfo app?

Have a nice day.

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[petercwallis]

That's right. 

I had noted I need to access blocks in some particular order for some tags, but this tag does not get past the NOTAG_ERROR signal from the MFRC522.

[fangfang]

Hello @petercwallis .

Thanks for your update information.

You may firstly read or writer NTAG213 via Taginfo app. And make sure if the tag is OK.

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[petercwallis]

Yes. Taginfo app can read the tag. And yes. It is seen as a NTAG213 by the Taginfo app.