PCA10056 version of adafruit_tag_reader example ends with err_code = 0x03

[JWizard]

I have the nRF52840-DK with the adafruit PN532 RFID/NFC shield installed on top of it.

I run the TWI Scanner and receive a report that a device was found at address 0x24.

I then load the .emproject for the adafruit tag reader example for the 10056. When I run this it eventually comes to a stop in app_error_weak.c at NRF_BREAKPOINT_COND. Prior to this adafruit_pn532_init(false) returns error_code = 0x03.

<info> adafruit_pn532: Creating I2C
<info> adafruit_pn532: Looking for PN532
<info> adafruit_pn532: Trying to get the firmware version
<info> adafruit_pn532: Trying to send command
<info> adafruit_pn532: 02 |.
<info> adafruit_pn532: Sending command
<info> adafruit_pn532: 00 00 FF 02 FE D4 02 2A|.......*
<info> adafruit_pn532: 00 |.
<info> adafruit_pn532: Failed while waiting
<info> adafruit_pn532: Failed to send GetFirmwareVersion command, err_code = 3
<info> adafruit_pn532: Didn't find PN53x board, err_code = 3
<error> app: ERROR 3 [NRF_ERROR_INTERNAL] at <my_path_to_sdk>\nRF5SDK160098a08e2\examples\nfc\adafruit_tag_reader\main.c:403
PC at: 0x0000395D
<error> app: End of error report

That's the output over UART. Interestingly before I enabled logging the execution was very difficult to follow. Seemed much was optimized away or executing in strange order.. I digress.

What would be causing the ERROR 3?

[JWizard]

Ha! The previous owner of my PN532 shield had cut the traces which take the IRQ signal out to the pin headers. False Alarm.