topic Re: Why is "LAST_NDEF_BLOCK" always zero in NFC

Why is "LAST_NDEF_BLOCK" always zero

gerrikoio — Sat, 09 May 2020 19:29:11 GMT

I recently got some PCB's made and populated these with some NT3H2111 and NT3H2211 NTAG I2C plus tags.

The NFC read and write from a phone using the various NXP NFC apps, such as TagWriter, TagInfo and NTAG I2C demo all work fine.

However with the TagInfo app, in EXTRA, it tells me that my last NDEF message page address has an error as this is 0x00.

When I read the capability container from I2C it confirms this too. LAST_NDEF_BLOCK: 0x00

I can still read/write NDEF message using the apps, but I cannot read these NDEF messages from I2C.

Is this normal with unconfigured NT3H2111/NT3H2211 tags?

Or, are there certain things I need to do to get these tags "ready" so that I can read/write from I2C and also ensure that the LAST_NDEF_BLOCK is correct. So, for example, what do I do with LAST_NDEF_BLOCK. Do I have to manually set this to 0x01 before use?

Re: Why is "LAST_NDEF_BLOCK" always zero

gerrikoio — Sat, 09 May 2020 21:02:27 GMT

Sorry I meant Session Registers not Capability Container for the byte LAST_NDEF_BLOCK which is set to 0x00 (default)

Re: Why is "LAST_NDEF_BLOCK" always zero

Jonathan_Iglesias — Wed, 13 May 2020 21:24:32 GMT

Hi Colin Gerrish

LAST_NDEF_BLOCK works as “monitor” which can be set to monitor a change of value in chosen UserMemory block. When value in that block changes, ED (interrupt) is fired. E.g. This can notify µC that it can start accessing eeprom.

User Memory can always be read by I²C if I2C_PROT is not 1b. Beware to use proper command formatting on i²C which differs from register access formatting, described on page 44 of Datasheet:

Jonathan

Re: Why is "LAST_NDEF_BLOCK" always zero

gerrikoio — Fri, 15 May 2020 09:54:49 GMT

LAST_NDEF_BLOCK works as “monitor” which can be set to monitor a change of value in chosen UserMemory block. When value in that block changes, ED (interrupt) is fired.

Please could you explain how this is done, both from I2C perspective and NFC perspective. I had somehow assumed that this was automatic and I did not realise it can be used to monitor a chosen UserMemory block, which is quite useful.

Re: Why is "LAST_NDEF_BLOCK" always zero

Jonathan_Iglesias — Thu, 28 May 2020 21:22:49 GMT

Please check the DS

there is an explanation of it in table 13. please check it.

https://www.nxp.com/docs/en/data-sheet/NT3H2111_2211.pdf?pspll=1

Jonathan