AnsweredAssumed Answered

nt3h2111 cannot activate pass-through

Question asked by Marek Wągrodzki on Sep 27, 2018
Latest reply on Sep 29, 2018 by emni petro


I'm developing a board with NT3H2111 NTAG I2C Plus IC. I want to use pass-through mode, but I'm having trouble activating it. I cannot write PTHRU_ON_OFF bit in NC_REG session register. I have no trouble with setting any other bit and reading it back via NFC, but when I set this specific one bit, it doesn't change. I know there need to be both interfaces reachable to activate pass-through, but there are. The alorithm is following:
-NTAG is powered down, MCU waits for the interrupt from GPIO connected to field detect pin

-when FD goes down (when I stick the phone to the atenna), the interrupt is being asserted

-during an interrupt, I power up the chip (tried powering it non-stop - didn't help) and write the session register NC_REG - I'm setting PTHROUGH_ON_OFF and TRANSFER_DIR bits to 1

-in the meantime I'm polling the PTHROUGH_ON_OFF bit on my phone, but it can never detect it

I tried reading the NC_REG from i2c right after writing it - it stays 0b all the time. What am I missing out?