topic Re: PN7160A and Compute Module 5 multiple problems in NFC

PN7160A and Compute Module 5 multiple problems

Zlutz — Tue, 17 Mar 2026 10:52:30 GMT

I made a CM5 board with two LAN ports and multiple other features, one of them being I2C version of PN7160. Everything works perfectly, but I can't make PN7160 work.

Schematic attached - maybe I made an obvious error?

I2C1 is used on pins 10 and 11 (3.3k pull-ups), address pins are connected to gpio8 and gpio9 (I hoped to maybe use SPI version of chip; SPI0 pins are alternative to I2C1; If I populate SPI version of PN7160 I just remove the I2C pull-ups and it should work!)

I modified boot/firmware/config.txt

----------------------
# PN7160A functionality

# Set I2C Address pins to Pull-Down (sets address to 0x28)
gpio=8=op,dl
gpio=9=op,dl
# enable I2C-1
dtoverlay=i2c1,pins_10_11
# GPIO23 is IRQ input, 24 is VEN, 25 is DWL_REQ. VEN and DWL_REQ start LOW!
gpio=23=ip,pd
gpio=24=op,dl
gpio=25=op,dl
----------------------

I can control all the pins (pinctrl set 24 dh turns the chip on)

First problem:

i2cdetect -y 1 doesn't detect anything. Does PN7160 even respond to this command or should I test it differently if it doesn't? Can I test it differently?

Probing SDA and SCL gives me nice waveforms on the scope, and it decodes data from 08W~a to 77W~a so CM5 I2C is definitely working. Clock is a 100kHz square wave, but it's not really a perfect 50% duty cycle, it's actually 60% low and 40% high. That's still in-spec, but could it be an issue?

setting GPIO24 (VEN) high - I can see that PN7160 starts oscillator and turns it off after exactly 1 second

setting GPIO25 (DWL_REQ) high before setting VEN high - oscillator doesn't even turn on so SOMETHING is working.

I suspected wrong load capacitors on the oscillator (18pF with 12pF <50ohm crystal), tried 12pF, 15pF and 22pF -> always the same so it's probably not the oscillator.

i2cdetect -y 1 simply doesn't detect anything.

Suggestion was to update the PN7160 firmware, but I can't do it without the NCI2 stack.

Any other suggestions? I plan to connect DS1337 RTCC to the same bus to see if that one will get detected just to completely exclude the thought that CM5 I2C might not be working correctly.

----------------------------------

Second problem - even after following the "Porting PN7160 NCI2 stack to Raspberry Pi 5 OS --Bookworm", it doesn't work and even after fixing a lot of code manually because newer compilers are more strict than the old ones, I get a bunch of errors like this:

no declaration matches 'int NfccAltTransport::verifyPin(int, int, int)'
no functions named 'int NfccAltTransport::verifyPin(int, int, int)'
error: 'gpiod_line_set_value' was not declared in this scope; did you mean 'gpiod_line_value'?
error: 'gpiod_line_get_value' was not declared in this scope; did you mean 'gpiod_line_value'?

...and many more, I can post a whole dump if needed... Is there a working git repository that I can use becuase this is simply taking too long

It's allegedly because I'm on the newest libgpiod-dev (Version: 2.2.1-2+deb13u1), but I don't really want to roll back to older libgpiod because I'm already using commands from the new one in my other software.

Newest linux for CM5 is not even bookworm anymore, it's 13.3 - trixie.

Should I find some older bookworm image with long term support or something - but something that will work? I don't mind using older software, but I still wouldn't like to release a new product that is "already outdated" even before release.

Re: PN7160A and Compute Module 5 multiple problems

Fabian_R — Wed, 18 Mar 2026 20:09:46 GMT

Hello,

Could you please clarify if you have tested your setup using our Evaluation Board: OM27160| Development Kits for PN7160 Plug'n Play NFC Controller | NXP Semiconductors

This will help us have better control of any hardware issues.

Regarding the use of i2cDetect unfortunately, PN7160 doesn't reply to this script.

As you already know, the address of the IC is determined by the configuration of the I2C_ADR pins.

Could you please clarify that you have followed the steps from PN7160 Linux porting guide without success.

I would be great to have a log for further reviewing.

Re: PN7160A and Compute Module 5 multiple problems

Zlutz — Thu, 19 Mar 2026 15:11:13 GMT

I didn't test the setup using Evaluation board, I designed more than a couple of RFID readers using MFRC500, PN512, CLRC663 and PN7462/PCA9430HK combo so I hoped this would be as straightforward. All the product were embedded microcontroller designs though, this is the first one using a Linux SBC. Our firmware developer did have more trouble with PN7462 and recommended not using a I2C PN7160A and suggested using SPI version PN7160B, but unfortunately the supply chain made me do PN7160A anyway...

I didn't follow this PDF you linked, the PDF date is "September 2021". I followed this guide:

https://community.nxp.com/t5/NFC-Knowledge-Base/Porting-PN7160-NCI2-stack-to-Raspberry-Pi-5-OS-Bookworm/ta-p/1977521

This guide is dated October 2024.

I did all the changes and more. Compile runs for a good while, but then it throws errors (attached).

Is there maybe a working repository that works with libgpiod-dev 2.2.1 and/or trixie linux?

PN7160 not replying to i2cDetect makes me hopeful that the hardware is actually working; Can I manually send something to I2C and see if I get a reply just to see if the hardware is working?