nfcpy

can't read/write a tag type 2 with acr122

Asked by olk

I have a nfc reader/writer acr122 and i tried the HelloWorld example. For some tags i can write and read the ndef message. In one case i take the message: No ndef tag. What is going wrong with these tags?
Can I make them ndef tags?
Is there any other way to read and write these tags?

If i try :
import nfc

def connected(tag):print tag

clf=nfc.ContactlessFrontend('usb')
clf.connect(rdwr={'on-connect':connected})

i get this:
Type2Tag ATQ=4400 SAK=00 UID=04742902772f84
<nfc.tag.tt2.Type2Tag object at 0x971518c>

Thanks in advance!

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Stephen Tiedemann
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Stephen Tiedemann (stephen-tiedemann) said : 		#1

Most likely you are using Mifare Classic tags. They are not supported by
nfcpy.

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olk (olgak) said : 		#2

No, I am using Mifare Ultralight. I read the tag with Android Nfc reader successfully (this gave me feedback about the type of the tag: MifareUltralight, NdefFormatable). And only when i write with a TagWriter i was able to read/write with nfcpy. It seems that the tags need initialization or sth ??!

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Best Stephen Tiedemann (stephen-tiedemann) said : 		#3

Yes, they need to be NDEF formatted. Otherwise there's nothing to show other than the tag identity. The NXP tool is the right tool to use, they certainly know about their different chip types to create the correct format.

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olk (olgak) said : 		#4

Thanks Stephen Tiedemann, that solved my question.