PN7160 Issues with NFC Discovery

[rolma]

Hi!

I’m working with the PN7160 (OM27160A1HN) development kit and interfacing it with an nRF microcontroller over I2C. I'm basing my code on the Read/Write example from NXP-NCI2.0_MCUXpresso_examples and have adapted the TML layer as recommended.

However, I’m facing an issue where NFC discovery detects no cards.

Problem description:

• I only modified the TML layer, leaving the rest of the code unchanged.
• I2C communication appears functional, messages are sent and acknowledged.
• PN7160 initializes without errors.
• During discovery:
  • The IRQ signal remains low.
  • The device stops responding (NACK) after the discovery command.
• The PN7160 is supplied with 5V.

Could this issue be related to power or the RF not being properly enabled?
What other debugging steps would you recommend?

Any insights would be highly appreciated.

Thank you in advance,

Marco

[Daniel_Gutierrez]

Hello @rolma, Good Day!

Thank you very much for your interest in our products.

Unfortunately, matters related to porting to third-party hosts are out of our support scope, since we may not be able to recreate the environment on which you are working.

I would suggest trying to make the PN7160 NXP-NCI MCUXpresso Example Project work with one of our recommended hosts such as LPC5500 Series or LPC800 Series microcontrollers from the LPC family or i.MX RT Series Crossover MCUs from the Crossover Processors family, to confirm that the PN7160 Front End Device is working properly.

Consider that, in order for the device to work as expected, signals from the NFC controller board must be connected and handled by the host. You could refer to section 2 of the NXP-NCI2.0 MCUXpresso examples guide to check which pins must be connected, and refer to PN7160/PN7161 Data Sheet  to find out more about the proper handling of the signals.

My best regards,
Daniel.

[rolma]

Hello Daniel,

Thank you for your response.

I will consider testing with an NXP kit, but I don't have any of them right now.

However, I am currently facing some issues with the power lines and would like to confirm whether my setup is correct, regardless of the microcontroller used.

This is what I have at the moment:

VDD_PAD = 1.8V
VDD_UP = VBAT = 5.0V

According to the documentation, VDD(TX) should be 5.0V - 0.3V, if I understood correctly, but I am measuring 2.4V instead.

At a firmware level, I only changed this value from 1 to 2:
#define NXP_TVDD_CONF 2 // 1=3.3V, 2=4.75V

I am observing the following behaviour in my setup:

A voltage drop occurs immediately after sending the RF Discovery command. And transient signal disturbances were still observed.

Following this disturbance, the PN7160 stops responding over I2C, consistently returning NACK to all subsequent communication attempts. Additionally, the IRQ signal remains inactive, indicating that the device is no longer detecting events or responding as expected.

The power supply should be sufficient, so I don’t believe this is the root cause.

This behaviour is completely repeatable, occurring in the same way on every attempt.

Could you confirm if these voltage levels are appropriate and if there are any additional steps I should take to debug this issue?

Best,

Marco

[Daniel_Gutierrez]

Hello @rolma, Good Day!

Please keep in mind that unfortunately, any support regarding the functionality of our library working on a third-party host is out of our scope.

However, given the information provided, it might be that the PN7160 is entering the ''standby'' mode given that, when in this state, VDD(TX) is regulated to around 2.5 V, no matter what value it has been set to, as mentioned in section 11.4.3.1 of the PN7160/PN7161 Data Sheet. Keep in mind that for proper operation, the VDD(TX) value set, must be LOWER than (VDD(UP) - 0.3 V).

Also, the NACK may be received when the reception buffer is not free which may also happen in ''standby'' mode.

To approach this issue, you may:

1. Disable standby mode using the CORE_SET_POWER_MODE_CMD with 0x00 as a parameter (see section 12.6.1 of PN7160 User Manual)
2. Assert the WUP_REQ pin to high. As long as this pin is enabled, the PN7160 will never go to standby. In order for this assertion to work you must configure the ''IRQ_POLARITY_CFG'' parameter with the CORE_SET_CONFIG_CMD (see section 13 of the latter document).
3. Make sure a correct handling of the VEN reset pin is taking place, given that, after the boot sequence, the default state should be Active and not standby. Please refer to section 11.5 of the first document to get a deeper understanding on possible power up sequences for a successful boot process and host communication.

My best regards,
Daniel.