Posted on September 22, 2017 at 14:54Hello,
The GPO pin of the ST25TA02K-P is an output-only signal used to trigger RF events
(see section 2.4 and section 11 of the
http://www.st.com/content/ccc/resource/technical/document/datasheet/f9/9f/ef/57/ef/20/48/d0/DM00179249.pdf/files/DM00179249.pdf/jcr:content/translations/en.DM00179249.pdf
).
In the diagram you are showing, a typical use-case would be to send a wakeup signal
from the ST25TA02K-P to the microcontroller on a user-defined RF event.
The GPO interface can not be used to transmit NDEF content.
I suggest you have a look at the
http://www.st.com/en/nfc/m24sr-series-dynamic-nfc-tags.html?querycriteria=productId=SS1812
product, which is a NFC Type 4A tag providing
a I2C interface that can be used to access the EEPROM.
Best regards