NFCのトピックRe: PN7642 LPUART_polling demo issue

PN7642 LPUART_polling demo issue

wangea — Fri, 22 May 2026 09:38:45 GMT

Hello @EduardoZamora,

I got a similar issue when using LPUART_polling SDK demo on our prototype, which had been reported on the forums linked https://community.nxp.com/t5/NFC/PN7642-resets-when-calling-LPUART-Init/m-p/1785561 & PN7642, LPUART examples not working - NXP Community I couldn't see the further solution. no I2C, I3C, SPI and USB interfaces used on our application.

There was no such issue with the demo examples hello_world or Blinky.

SO what is the reason for this issue and how can we reslove it ?

with the reset chip, it couldn't be connected with Jlink. Is this recoverable？if yes, how?

Regards.

Ethan.

Re: PN7642 LPUART_polling demo issue

EduardoZamora — Fri, 22 May 2026 21:29:55 GMT

Hello @wangea

Hope you are doing well.

I can see that your custom board uses C101 variant. C101 uses FW v2.00 by default, and something important to remark is that an SDK is bound to a certain FW version. If your SDK version does not correspond to the FW version, some unexpected behavior may occur.

Please try updating your firmware version through ay of the available methods described in Firmware update on PN7642.

Regards,
Eduardo.

Re: PN7642 LPUART_polling demo issue

wangea — Mon, 25 May 2026 09:09:39 GMT

Hello @EduardoZamora,

Appreciate for your quick response.

I had updated the fw to v3.00 using SDK version 2.15.006, since there is only one prototype left, i will take the verification for the lpuart after other function testing done.

Currently, I got another issue about RF distance when using the nfc example(pnev7642fama_NfcrdlibEx4_MIFAREClassic_Freertos_Pub). The RF distance is only 2 cm, which is much smaller than the maximum distance supported by the PN7642. since there is no usb inferface used on our prototype, i added some configurations in the sw instead of NFC Cockpit, Shown as below, attached is the detailed implements for each fuction. Besides, i had read RX_CONTROL_STATUS register (0x28) and found HF_ATT_VALUE was always 63, even Increase or decrease RRx

pn7642 works in boost mode, and the antenna range is approximately 40*60 mm

My question is:

Are the configurations correct or enough? If not, what should i do to improve the RF distance.

Best Regards.

Ethan.