NFC Writable NDEF Message¶

Overview¶

The NFC Writable NDEF Message sample shows how to use the NFC tag to expose an NDEF message that can be overwritten with any other NDEF message by an NFC device. It uses the NFC Data Exchange Format (NDEF) library.

When the sample starts, it initializes the NFC tag and loads the NDEF message from the file in flash memory. If the NDEF message file does not exist, a default message is generated. It is a URI message with a URI record containing the URL "https://makerdiary.com". The sample then sets up the NFC library for the Type 4 Tag platform, which uses the NDEF message and senses the external NFC field.

The library works in Read-Write emulation mode. In this mode, procedures for reading and updating an NDEF message are handled internally by the NFC library. Any changes to the NDEF message update the NDEF message file stored in flash memory.

The Green LED indicates if an NFC field is present. Press the USR button during startup to restore the default NDEF message.

Requirements¶

Before you start, check that you have the required hardware and software:

1x nRF54L15 Connect Kit
1x U.FL cabled 13.56 MHz NFC Antenna (included in the box)
1x USB-C Cable
A smartphone or a tablet with NFC support
A computer running macOS, Ubuntu, or Windows 10 or newer

Installing NFC Tools App¶

NFC Tools App can read and write your NFC tags with a simple and lightweight user interface.

Attaching the NFC antenna¶

Before applying power to the board, ensure the U.FL cabled NFC antenna is properly installed.

Building the sample¶

To build the sample, follow the instructions in Getting Started Guide to set up your preferred building environment.

Use the following steps to build the NFC Writable NDEF Message sample on the command line.

Open a terminal window.
Go to NCS-Project/nrf54l15-connectkit repository cloned in the Getting Started Guide.
Build the sample using the west build command, specifying the board (following the -b option) as nrf54l15_connectkit/nrf54l15/cpuapp.
```
west build -p always -b nrf54l15_connectkit/nrf54l15/cpuapp samples/nfc/writable_ndef_msg
```
Tip

The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.
After building the sample successfully, the firmware with the name merged.hex can be found in the build directory.

Flashing the firmware¶

Connect the nRF54L15 Connect Kit to the computer with a USB-C cable:

Then flash the sample using west flash:

west flash

Tip

In case you wonder, the west flash will execute the following command:

pyocd load --target nrf54l --frequency 4000000 build/merged.hex

Testing¶

After programming the sample, test it by performing the following steps:

Open up a serial terminal, specifying the primary COM port that your computer uses to communicate with the nRF54L15:
WindowsmacOSUbuntu
1. Start PuTTY.
2. Configure the correct serial port and click Open:
Open up a terminal and run:
screen <serial-port-name> 115200
Open up a terminal and run:
screen <serial-port-name> 115200
Press the DFU/RST button to reset the nRF54L15.

Once the sample starts running, you should see the following output:

Terminal
*** Booting nRF Connect SDK v3.1.0-6c6e5b32496e ***
*** Using Zephyr OS v4.1.99-1612683d4010 ***
Starting NFC Writable NDEF Message sample
NDEF file record not found, creating default NDEF.

Touch the NFC antenna with the smartphone or tablet and observe that Green LED blinks.
Observe that the smartphone or tablet tries to open the URL "https://makerdiary.com" in a web browser.
Open NFC Tools app, tap the Write tab at the bottom of the screen and tap + Add a record to add your new NDEF records.
Tap Write and touch the NFC antenna again to write the new message. If successful, you will see the following output:
Terminal
5
NDEF message successfully flashed.
Go back to the Read tab and rescan the tag to confirm your new message appears.