I'm using this NFC reader and here there all the documents.
Without issuing any command it works in freerun mode, reading out any NFC tag in the nearby. But it uses the internal antenna.
In the datasheet there is the command to switch to the external antenna:
Enable External Antenna: 01080003042B0000
But after that it seems the freerun mode is disabled, and I'm not able to detect tags anymore.
Does anyone have experience with this device?