NFC hang after RF_ON command

Question

We have developed our board with PN5180 NFC but I cannot make it work properly. After I send RF_ON command I am stuck on STATE_CHANGE_IRQ_STAT while waiting for TX_RFON_IRQ_STAT but the state never changes. In this moment I can see sinus vawes on the oscilloscope. If I ignore it I will be stuck waiting for the RX_STATUS register to reflect the TRANSCEIVE_STATE. If I ignore both, the TX_RFON_IRQ_STAT appears after few SEND_DATA sequences but card cannot be read. Has anyone experience this?

def init(self):

# 1. Loads the ISO 15693 protocol into the RF registers
self._send([LOAD_RF_CONFIG, 0x00, 0x80])

# 2. Switches the RF field ON.
self._send([RF_ON, 0x00])


answer = self.read_irq_status_register()
while ((TX_RFON_IRQ_STAT & answer) == 0):
  answer = self.read_irq_status_register()
  self.show_status(answer)

return 1

Answer 1

The solution is that PN5180 simply cannot work without BUSY pin connected.