nfc uart poller is not working

[weizhen]

I am working on the nfc uart examples. first I found the poller example is not support for 10056 board. I make the change for that. code can build and flashed, but then I received the error code 

<error> app: ERROR 33281 [NRF_ERROR_DRV_TWI_ERR_ANACK] at ../../../main.c:300

PC at: 0x000045BB

<error> app: End of error report

it happened on adafruit_pn532_init

Do you know what's wrong with the example? and how to fix that?

[weizhen]

figured the poller requires the nfc reader module. never mind. 

[Karl Ylvisaker]

Hello,

Could you specify exactly which example you have modified to work with the nRF52840 DK?
The NRF_ERROR_DRV_TWI_ERR_ANACK error means that the TWI slave has not acknowledged the TWI transfer. This could be a result of an erronus connection between the two devices, or if there is anything preventing the TWI slave from receiving/acknowledging the transfer.

Please note that the nRF52840 DK does not have a PN532 on board, and so you would have to connect this module externally.
Could you detail how this connection is made? Preferably with a connection diagram where you note which pins are connected to which pin on the opposing device.

Best regards,
Karl

[Karl Ylvisaker]

Ah, I did not see this comment before I wrote my previous answer.
You will indeed need the external PN532 module to run this example successfully. If you acquire one of these shields you can run this example.
You can read more about this in the example documentation.

Please do not hesitate to open another ticket if you should encounter any other issues or questions in the future! :) 

Best regards,
Karl