Problem reading an ISO 15693 Tag with PN7120 in Android

[jschmuc]

Hi there,

we are having problems reading ISO 15693 Tags with the PN7120 in Android:

First, reading works as expected, but after a few times the reader stops and won't read any tags anymore. The last message read from the PN7120 is always this:

05-25 11:06:44.519   345  1576 D NxpTml  : PN54X - I2C Read successful.....
05-25 11:06:44.519   345  1576 D NxpNciR : len =   4 > 00000102
05-25 11:06:44.519   345  1576 D NxpTml  : PN54X - Posting read message.....
05-25 11:06:44.519   345  1579 D NxpHal  : read successful status = 0x0
05-25 11:06:44.520  1330  1538 I libnfc_nci: [INFO:gki_buffer.cc(307)] GKI_getbuf 0xb400006fdf3194a0 30:33
05-25 11:06:44.520  1330  1566 I libnfc_nci: [INFO:nfc_ncif.cc(420)] NFC received data
05-25 11:06:44.520  1330  1566 I libnfc_nci: [INFO:nfc_ncif.cc(1918)] nfc_ncif_proc_data 0x000001
05-25 11:06:44.520  1330  1566 I libnfc_nci: [INFO:nfc_ncif.cc(1923)] nfc_ncif_proc_data len:1
05-25 11:06:44.521  1330  1566 I libnfc_nci: [INFO:rw_i93.cc(3256)] rw_i93_data_cback - event = 0x6003
05-25 11:06:44.521  1330  1566 I libnfc_nci: [INFO:rw_i93.cc(3321)] rw_i93_data_cback - RW I93 state: <BUSY (2)>

A reset of the PN7120 (via Android NFC-Service) fixes the problem until it arises again.

So from the libnfc_nci code it seems that the PN7120 sends an I93_FLAG_ERROR_DETECTED without any error code and won't read afterwards.

Is there any possibility to further debug this issue. E.g. an NCI message to read out the state / some error information from the PN7120?

I also attached a log of the last reads with debugging enabled.

[KaiLi]

Hello @jschmuc 

From the log you provided, it seems that the tag that you used is not the standard 15693, or is not an NXP product at least, so it is recommended that you test it  again with NXP's ICODE tag. The following log compares between me and you for reference.